[testing] Print something for log classifier to better differentiate reruns vs real failures (#165163)

The normal pytest/unittest failure patterns also match flaky tests (specifically I think tests that fail -> succeed on rerun in a new subprocess)

So print something specifically for log classifier that it can match against
Pull Request resolved: https://github.com/pytorch/pytorch/pull/165163
Approved by: https://github.com/izaitsevfb

test/run_test.py

@@ -774,6 +774,9 @@ def run_test_retries(
                 "Test succeeeded in new process, continuing with the rest of the tests"
             )
         elif num_failures[current_failure] >= 3:
+            # This is for log classifier so it can prioritize consistently
+            # failing tests instead of reruns. [1:-1] to remove quotes
+            print_to_file(f"FAILED CONSISTENTLY: {current_failure[1:-1]}")
             if not continue_through_error:
                 print_to_file("Stopping at first consistent failure")
                 break