Ok. Performance improvement comes from:

a. Presizing
b. Bypassing some checks in PyDict_SetItem
c. Avoiding duplication check.

(b) is relatively small so I tried to focus on (a) and (b). See GH-22909.

In case of simple keyword arguments, it is 10% faster than GH-22346:

```
$ ./python -m pyperf timeit --compare-to ./python-speedup_kw "dict(ihinvdono='doononon', gowwondwon='nwog', bdjbodbob='nidnnpn', nwonwno='vndononon', dooodbob='iohiwipwgpw', doidonooq='ndwnnpnpnp', fndionqinqn='ndjboqoqjb', nonoeoqgoqb='bdboboqbgoqeb', jdnvonvoddo='nvdjnvndvonoq', njnvodnoo='hiehgieba', nvdnvwnnp='wghgihpa', nvfnwnnq='nvdknnnqkm', ndonvnipnq='fndjnaobobvob', fjafosboab='ndjnodvobvojb', nownwnojwjw='nvknnndnow', niownviwnwnwi='nownvwinvwnwnwj')"
python-speedup_kw: ..................... 357 ns +- 10 ns
python: ..................... 323 ns +- 4 ns

Mean +- std dev: [python-speedup_kw] 357 ns +- 10 ns -> [python] 323 ns +- 4 ns: 1.11x faster (-10%)
```

In case of `dict(d, key=val)` case, it is 8% slower than GH-22346, but still 8% faster than master.

```
$ ./python -m pyperf timeit --compare-to ./python-speedup_kw -s 'd={"foo":"bar"}' "dict(d, ihinvdono='doononon', gowwondwon='nwog', bdjbodbob='nidnnpn', nwonwno='vndononon', dooodbob='iohiwipwgpw', doidonooq='ndwnnpnpnp', fndionqinqn='ndjboqoqjb', nonoeoqgoqb='bdboboqbgoqeb', jdnvonvoddo='nvdjnvndvonoq', njnvodnoo='hiehgieba', nvdnvwnnp='wghgihpa', nvfnwnnq='nvdknnnqkm', ndonvnipnq='fndjnaobobvob', fjafosboab='ndjnodvobvojb', nownwnojwjw='nvknnndnow', niownviwnwnwi='nownvwinvwnwnwj')"
python-speedup_kw: ..................... 505 ns +- 15 ns
python: ..................... 546 ns +- 17 ns

Mean +- std dev: [python-speedup_kw] 505 ns +- 15 ns -> [python] 546 ns +- 17 ns: 1.08x slower (+8%)

$ ./python -m pyperf timeit --compare-to ./python-master -s 'd={"foo":"bar"}' "dict(d, ihinvdono='doononon', gowwondwon='nwog', bdjbodbob='nidnnpn', nwonwno='vndononon', dooodbob='iohiwipwgpw', doidonooq='ndwnnpnpnp', fndionqinqn='ndjboqoqjb', nonoeoqgoqb='bdboboqbgoqeb', jdnvonvoddo='nvdjnvndvonoq', njnvodnoo='hiehgieba', nvdnvwnnp='wghgihpa', nvfnwnnq='nvdknnnqkm', ndonvnipnq='fndjnaobobvob', fjafosboab='ndjnodvobvojb', nownwnojwjw='nvknnndnow', niownviwnwnwi='nownvwinvwnwnwj')"
python-master: ..................... 598 ns +- 10 ns
python: ..................... 549 ns +- 19 ns

Mean +- std dev: [python-master] 598 ns +- 10 ns -> [python] 549 ns +- 19 ns: 1.09x faster (-8%)
```

Additionally, I expect we can reuse this new code to optimize BUILD_CONST_KEY_MAP.