bpo-36475: Finalize PyEval_AcquireLock() and PyEval_AcquireThread() properly (GH-12667)

PyEval_AcquireLock() and PyEval_AcquireThread() now
terminate the current thread if called while the interpreter is
finalizing, making them consistent with PyEval_RestoreThread(),
Py_END_ALLOW_THREADS, and PyGILState_Ensure().