[pull] main from python:main - #1398

…GH-156107)

Test setting a value of an accepted type, of a wrong type and an invalid
value, and deleting the attribute, for the attributes defined with
PyMemberDef and PyGetSetDef which were not covered.

setcchar() takes a NUL-terminated string, so a NUL sharing a cell dropped
the rest of the cell, and an empty cell read back as complexchar('').

Reject a NUL that shares a cell or that joins a complexstr, and read an
empty cell as complexchar('\0'), as a narrow build already does.

… type cache (#155391)

…on (#156102)

…reads (gh-153462)

Co-authored-by: Timofey Ivankov <playboicartina@gmail.com>