[cmaloney]

Argument Clinic @vectorcall generation accepted *args parameters but the generated code expected an argument tuple. The first commit uses the fastcall form to parse the args array making it work right.

zip previously hand coded argument parsing and had no vectorcall. Argument error messages are unchanged except for unknown keywords: zip(strict=1, x=2) now reports "got an unexpected keyword argument 'x'" instead of "takes at most 1 keyword argument (2 given)". The docstring gains a summary line; __text_signature__ is unchanged.

pyperf microbenchmark (PGO+LTO, run serially):

Benchmark	base	zip
zip(a, b, strict=True)	118 ns	61.5 ns: 1.92x faster
zip(a, b)	64.9 ns	53.1 ns: 1.22x faster
zip(a)	55.0 ns	47.1 ns: 1.17x faster
list(zip(a, b))	123 ns	113 ns: 1.09x faster
zip()	27.4 ns	25.7 ns: 1.07x faster
Sub(a, b)	71.5 ns	70.6 ns: 1.01x faster

Benchmark hidden because not significant (1): zip.__new__

Benchmark code:

import pyperf

runner = pyperf.Runner()
setup = "a = (1, 2, 3); b = [4, 5, 6]"
for stmt in ["zip()", "zip(a)", "zip(a, b)", "zip(a, b, strict=True)",
             "list(zip(a, b))"]:
    runner.timeit(stmt, stmt, setup)
runner.timeit('zip.`__new__`', 'new(zip, a, b)', setup + '; new = zip.__new__')
runner.timeit('Sub(a, b)', 'S(a, b)', setup + '\nclass S(zip): pass')

• Issue: Generate vectorcall code to parse arguments using Argument Clinic #87613