gh-155109: Run tests exhausting the C stack with a limited C stack (GH-155120)

gh-155109: Run tests exhausting the C stack with a limited C stack (GH-155120)

Add the @support.run_with_limited_c_stack() decorator which runs the test
in a thread with a 8 MiB C stack, so that the outcome does not depend on
RLIMIT_STACK. Use it in tests which recurse to a fixed depth --
@support.skip_if_huge_c_stack() failed to skip them with a 16 MiB stack.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>