[3.15] gh-151278: Fix test_faulthandler on UBSan (GH-151279) (#151281)

gh-151278: Fix test_faulthandler on UBSan (GH-151279)

* Py_FatalError() no longer calls _PyFaulthandler_Fini() if it
  doesn't hold the GIL.
* Skip test_faulthandler tests raising signals if run with UBSan.
* Enable test_faulthandler in GitHub Action "Reusable Sanitizer".
(cherry picked from commit e60c42dc3f)

Co-authored-by: Victor Stinner <vstinner@python.org>

Python/pylifecycle.c

@@ -3724,7 +3724,9 @@ fatal_error(int fd, int header, const char *prefix, const char *msg,
        This function already did its best to display a traceback.
        Disable faulthandler to prevent writing a second traceback
        on abort(). */
-    _PyFaulthandler_Fini();
+    if (has_tstate_and_gil) {
+        _PyFaulthandler_Fini();
+    }
 
     /* Check if the current Python thread hold the GIL */
     if (has_tstate_and_gil) {