[3.13] gh-117657: Fix TSAN race involving import lock (GH-118523) (#120169)

[3.13] gh-117657: Fix TSAN race involving import lock (GH-118523) (#120169)

This adds a `_PyRecursiveMutex` type based on `PyMutex` and uses that
for the import lock. This fixes some data races in the free-threaded
build and generally simplifies the import lock code.
(cherry picked from commit e21057b99967eb5323320e6d1121955e0cd2985e)

Co-authored-by: Sam Gross <colesbury@gmail.com>