Fix calling order of PyEval_InitThreads. (GH-15836)

As described in Doc/c-api/init.rst, PyEval_InitThreads() cannot be called
before Py_Initialize() function.
(cherry picked from commit 9e61066355b4b55c873d56f5f106a22463b56862)

Co-authored-by: Kenta Murata <mrkn@users.noreply.github.com>
1 file changed