bpo-20891: Fix PyGILState_Ensure() (#4650) (#4657)

When PyGILState_Ensure() is called in a non-Python thread before
PyEval_InitThreads(), only call PyEval_InitThreads() after calling
PyThreadState_New() to fix a crash.

(cherry picked from commit b4d1e1f7c1af6ae33f0e371576c8bcafedb099db)
2 files changed