Add specialized argument parsing functions for these simple signatures:

1. No arguments
2. Single argument
3. No keyword-only args, *kwargs or **kwargs

The latter case covers many typical functions, such as these:

def f(x: int, y: int) -> int: ...
def g(x: int = 0) -> str: ...

The new parsing functions take a fast path when the caller passes only positional
arguments. This speeds up wrapper functions a lot in simple calls.

Microbenchmark speedups:

• positional_args_from_interpreted is 1.5x faster (now faster than interpreted)
• nested_func is 1.5x faster
• sorted_with_key is 14% faster (now faster than interpreted)