Reduce number of invalidations

[nalimilan]

SnoopCompile indicates that most of invalidations are due to overwriting Base._promote_typesubtract which ideally wouldn't be needed, see JuliaLang/julia#38241) and from convert(::Type{Any}, x::TypedMissing), which I added to fix a method ambiguity. Maybe these could be alleviated if Base defined methods for AbstractMissing so that we don't have to redefine them.

julia> using SnoopCompile

julia> inv = @snoopr using TypedMissings

julia> invalidation_trees(inv)
9-element Vector{SnoopCompile.MethodInvalidations}:
 inserting isless(x::Missing, y::TypedMissing) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:260 invalidated:
   backedges: 1: superseding isless(::Missing, ::Any) in Base at missing.jl:87 with MethodInstance for isless(::Missing, ::Any) (1 children)
   43 mt_cache

 inserting *(d::Union{AbstractChar, AbstractString}, x::TypedMissing) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:407 invalidated:
   mt_backedges: 1: signature Tuple{typeof(*), String, Any} triggered MethodInstance for Logging.default_metafmt(::Base.CoreLogging.LogLevel, ::Any, ::Any, ::Any, ::Any, ::Any) (0 children)
                 2: signature Tuple{typeof(*), String, Any} triggered MethodInstance for Pkg.Registry.var"#update#54"(::IO, ::Bool, ::typeof(Pkg.Registry.update), ::Vector{Pkg.Registry.RegistrySpec}) (2 children)

 inserting ==(x::TypedMissing, ::Any) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:236 invalidated:
   backedges: 1: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Any, ::Task) (1 children)
              2: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Any, ::Base.UUID) (1 children)
              3: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Any, ::Symbol) (6 children)

 inserting ==(::Any, y::TypedMissing) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:237 invalidated:
   backedges: 1: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Base.UUID, ::Any) (1 children)
              2: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Module, ::Any) (1 children)
              3: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Method, ::Any) (1 children)
              4: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Core.TypeName, ::Any) (2 children)
              5: superseding ==(x, y) in Base at Base.jl:119 with MethodInstance for ==(::Symbol, ::Any) (4 children)

 inserting isequal(x::TypedMissing, y) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:247 invalidated:
   backedges: 1: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Any, ::Task) (3 children)
              2: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Any, ::Base.UUID) (4 children)
              3: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Any, ::Symbol) (89 children)

 inserting isequal(x, y::TypedMissing) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:248 invalidated:
   backedges: 1: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Base.UUID, ::Any) (3 children)
              2: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Module, ::Any) (4 children)
              3: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Method, ::Any) (23 children)
              4: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Symbol, ::Any) (33 children)
              5: superseding isequal(x, y) in Base at operators.jl:140 with MethodInstance for isequal(::Core.TypeName, ::Any) (68 children)

 inserting ismissing(::TypedMissing) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:154 invalidated:
   backedges: 1: superseding ismissing(x) in Base at essentials.jl:828 with MethodInstance for ismissing(::Any) (225 children)

 inserting convert(::Type{Any}, x::TypedMissing) in TypedMissings at /home/milan/.julia/dev/TypedMissings/src/TypedMissings.jl:226 invalidated:
   backedges: 1: superseding convert(::Type{Any}, x) in Base at essentials.jl:217 with MethodInstance for convert(::Type{Any}, ::Any) (534 children)

 deleting _promote_typesubtract(a) in Base at promotion.jl:162 invalidated:
   backedges:  1: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Nothing}) (1 children)
               2: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{DataType}) (1 children)
               3: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Vector{String}}) (1 children)
               4: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{NamedTuple{(:name, :uuid), _A}} where _A<:Tuple{Union{Nothing, String}, Union{Nothing, Base.UUID}}) (1 children)
               5: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Symbol}) (2 children)
               6: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Bool}) (2 children)
               7: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Tuple{Symbol, Symbol}}) (2 children)
               8: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{<:Tuple}) (2 children)
               9: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Union{}}) (3 children)
              10: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Tuple{String, VersionNumber}}) (3 children)
              11: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Dates.DateTime}) (3 children)
              12: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Module}) (4 children)
              13: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type) (5 children)
              14: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Tuple{String, Nothing}}) (7 children)
              15: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Any}) (8 children)
              16: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Float64}) (10 children)
              17: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Base.UUID}) (18 children)
              18: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{String}) (36 children)
              19: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::DataType) (37 children)
              20: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Type{Expr}) (49 children)
              21: superseding _promote_typesubtract(a) in Base at promotion.jl:162 with MethodInstance for Base._promote_typesubtract(::Any) (406 children)