process replay: show errors when updating refs (#25460)

* Update test_processes.py

* Apply suggestions from code review
old-commit-hash: d7095d0d43

selfdrive/test/process_replay/test_processes.py

@@ -247,6 +247,10 @@ if __name__ == "__main__":
     else:
       print("TEST SUCCEEDED")
 
+  else:
+    if failed:
+      print(diff1)
+      print("FAILED TO UPDATE REFS")
     else:
       with open(REF_COMMIT_FN, "w") as f:
         f.write(cur_commit)