code-gen: throw when generated queryBuilder function is awaited

[dirkdev98]

This may prevent some errors, and improves on th readability of existing errors when doing const [foo] = await queryFoo();

[github-actions]

==== Benchmark result ====

Node.js version: 14
Total benchmarks: 15
          Passed: 15
          Failed: 0
-----------
router - github static path              200000  iterations    9488  ns/op
router - github path params              100000  iterations   10713  ns/op
compas validator simple                 5000000  iterations     282  ns/op
yup validator simple                     100000  iterations   13045  ns/op
fastest-validator validator simple     10000000  iterations     104  ns/op
compas validator nested                 1000000  iterations    1462  ns/op
yup validator nested                      50000  iterations   46526  ns/op
fastest-validator validator nested      2000000  iterations     579  ns/op
logger - strings                         500000  iterations    2778  ns/op
logger - objects                         500000  iterations    3199  ns/op
logger - deep objects                    500000  iterations    5729  ns/op
uuid                                    2000000  iterations     598  ns/op
uuid.isValid                           10000000  iterations     141  ns/op
isNil                                 500000000  iterations       0  ns/op
isPlainObject                         100000000  iterations      19  ns/op

[github-actions]

==== Benchmark result ====

Node.js version: 15
Total benchmarks: 15
          Passed: 15
          Failed: 0
-----------
router - github static path              200000  iterations    6766  ns/op
router - github path params              200000  iterations    8430  ns/op
compas validator simple                 5000000  iterations     224  ns/op
yup validator simple                     100000  iterations   10839  ns/op
fastest-validator validator simple     10000000  iterations     102  ns/op
compas validator nested                 1000000  iterations    1285  ns/op
yup validator nested                      50000  iterations   33725  ns/op
fastest-validator validator nested      5000000  iterations     477  ns/op
logger - strings                         500000  iterations    2280  ns/op
logger - objects                         500000  iterations    2796  ns/op
logger - deep objects                    500000  iterations    4892  ns/op
uuid                                    5000000  iterations     325  ns/op
uuid.isValid                           10000000  iterations     137  ns/op
isNil                                 500000000  iterations       0  ns/op
isPlainObject                         100000000  iterations      18  ns/op

[github-actions]

==== C8 test coverage ====
Statements: 65.78% ( 24226/36830 )
Branches : 66.15% ( 2677 /4047 )
Functions : 65.3% ( 794 /1216 )
Lines : 65.78% ( 24226 /36830 )