perf(trie-router): avoid calling spread operator for Object.create(null)

[usualoma]

This optimization is based on the discussion in the following Pull Request.
Thanks to @EdamAme-x!
#3732

benchmarks

via benchmarks/routers

node

• all together
----------------------------------------------------------------------- -----------------------------
Hono RegExpRouter                   513 ns/iter       (490 ns … 715 ns)    524 ns    595 ns    715 ns
Hono TrieRouter(perf-trie-1208)   1'716 ns/iter   (1'652 ns … 1'895 ns)  1'723 ns  1'892 ns  1'895 ns
Hono TrieRouter(main)             2'203 ns/iter   (2'097 ns … 2'730 ns)  2'213 ns  2'709 ns  2'730 ns

summary for all together
  Hono RegExpRouter
   3.35x faster than Hono TrieRouter(perf-trie-1208)
   4.3x faster than Hono TrieRouter(main)

bun

• all together
----------------------------------------------------------------------- -----------------------------
Hono RegExpRouter                   393 ns/iter       (360 ns … 722 ns)    390 ns    594 ns    722 ns
Hono TrieRouter(perf-trie-1208)   3'191 ns/iter   (2'032 ns … 3'602 ns)  3'351 ns  3'595 ns  3'602 ns
Hono TrieRouter(main)             3'971 ns/iter   (3'732 ns … 4'293 ns)  4'065 ns  4'267 ns  4'293 ns

summary for all together
  Hono RegExpRouter
   8.12x faster than Hono TrieRouter(perf-trie-1208)
   10.1x faster than Hono TrieRouter(main)

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.73%. Comparing base (50ff212) to head (eac0056).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3735      +/-   ##
==========================================
+ Coverage   91.72%   91.73%   +0.01%     
==========================================
  Files         159      159              
  Lines       10184    10176       -8     
  Branches     2990     2873     -117     
==========================================
- Hits         9341     9335       -6     
+ Misses        842      840       -2     
  Partials        1        1              

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[usualoma]

There was a slight performance drop due to the eac0056 bug fix commit, but I still think it's the fastest.

[yusukebe]

LGTM!

[yusukebe]

I also like the not-magical way. This is simple and good!

Thanks, @usualoma @EdamAme-x !