bpo-23689: re module, fix memory leak when a match is terminated by a signal or memory allocation failure

[ghost]

@serhiy-storchaka , please review the commits one by one.

MSVC 2022 non-PGO release build, run test_re.py. It's a bit slower.

(best of 10)
Before: 0.278 sec
After:  0.283 sec

But when switching REPEAT very frequently, it has some speed up:

import pyperf

setup = ("import re;"
         "s = 100_000_000 * 'a';"
         "p = r'.*?(?:bb)+';"
         "p = re.compile(p)")
stmt = "p.match(s)"

runner = pyperf.Runner()
runner.timeit("match", stmt=stmt, setup=setup)

# Before: Mean +- std dev: 1.88 sec +- 0.03 sec
# After:  Mean +- std dev: 1.63 sec +- 0.03 sec

https://bugs.python.org/issue23689

[serhiy-storchaka]

My internet connection is very bad last days, so it will take a time for review, sorry.

[ghost]

It doesn't matter.