python3Packages.pygame: add traceback for segfaults in checkPhase

pkgs/development/python-modules/pygame/default.nix

···
     # No audio or video device in test environment
     export SDL_VIDEODRIVER=dummy
     export SDL_AUDIODRIVER=disk
+    # traceback for segfaults
+    export PYTHONFAULTHANDLER=1
 
     ${python.interpreter} -m pygame.tests -v \
       --exclude opengl,timing \