rollback 005fd1fe31ab (see #14609 and #14582)

Being able to overload a sys.module entry during import of a module was broken
by this changeset.
diff --git a/Python/importlib.h b/Python/importlib.h
index 392b941..6279e00 100644
--- a/Python/importlib.h
+++ b/Python/importlib.h
Binary files differ