This approach eliminates the originally reported race. It also gets rid of the deadlock reported in gh-96071, so we can remove the workaround added then.
This is mostly a cherry-pick of 1c0a104 (AKA gh-126989). The difference is we add PyInterpreterState.threads_preallocated at the end of PyInterpreterState, instead of adding PyInterpreterState.threads.preallocated. That avoids ABI disruption.
When formatting the AST as a string, infinite values are replaced by
1e309, which evaluates to infinity. The initialization of this string
replacement was not thread-safe in the free threading build.
(cherry picked from commit 427dcf24de)
Revert the incremental GC in 3.13, since it's not clear that without further turning, the benefits outweigh the costs.
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
