Added a patch that disables the invalid parameter handler in new_threadstate() so that all Python threads are protected from termination.

_PyVerify_fd is still moved into fileutils.c, but _Py_BEGIN/END_SUPPRESS_IPH and _Py_VERIFY_FD are gone. For VC14, _PyVerify_fd simply calls _get_osfhandle and checks the result.

As it's a hack, I haven't updated any documentation to draw attention to this, but I hope this is simpler enough that we can get Windows builds going again.