Improve performance of `find_max_char`

Feature or enhancement

Proposal:

find_max_char is called each time a string is created.
By reducing the amount of tests, the performance can be improved considerably.

python -m pyperf timeit -s "b=('a' *1000+ '\u019f'*2)" "b[:-1]"

+-----------+--------+----------------------+
| Benchmark | ref    | patch                |
+===========+========+======================+
| timeit    | 442 ns | 388 ns: 1.14x faster |
+-----------+--------+----------------------+

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-122902

Comece localizando a implementação de find_max_char no CPython e execute o comando pyperf fornecido com o comportamento atual. Compare o resultado do benchmark com a referência informada de 442 ns e o resultado do patch de 388 ns; considera-se concluído quando a abordagem de testes reduzida melhora o desempenho sem alterar o comportamento de criação de strings.