Move the removal of flaky tests from previous run to also take place in singlethreaded runs. (#25269)

Author: juj

test/parallel_testsuite.py

@@ -111,9 +111,6 @@ def run(self, result):
     # issues.
     # multiprocessing.set_start_method('spawn')
 
-    # Remove any old stale list of flaky tests before starting the run
-    utils.delete_file(common.flaky_tests_log_filename)
-
     tests = self.get_sorted_tests()
     contains_browser_test = any(test.is_browser_test() for test in tests)
     use_cores = cap_max_workers_in_pool(min(self.max_cores, len(tests), num_cores()), contains_browser_test)

test/runner.py

@@ -562,6 +562,9 @@ def set_env(name, option_value):
 
   check_js_engines()
 
+  # Remove any old test files before starting the run
+  utils.delete_file(common.flaky_tests_log_filename)
+
   def prepend_default(arg):
     if arg.startswith('test_'):
       return default_core_test_mode + '.' + arg