run_tests.py --auto_set_flakes should be disabled by default

tools/run_tests/run_tests.py

@@ -1420,16 +1420,18 @@ argp.add_argument(
     nargs='?',
     help='Upload test results to a specified BQ table.')
 argp.add_argument(
-    '--disable_auto_set_flakes',
+    '--auto_set_flakes',
     default=False,
     const=True,
     action='store_const',
-    help='Disable rerunning historically flaky tests')
+    help=
+    'Allow repeated runs for tests that have been failing recently (based on BQ historical data).'
+)
 args = argp.parse_args()
 
 flaky_tests = set()
 shortname_to_cpu = {}
-if not args.disable_auto_set_flakes:
+if args.auto_set_flakes:
     try:
         for test in get_bqtest_data():
             if test.flaky: flaky_tests.add(test.name)

tools/run_tests/run_tests_matrix.py

@@ -529,7 +529,6 @@ if __name__ == "__main__":
         extra_args.append('--bq_result_table')
         extra_args.append('%s' % args.bq_result_table)
         extra_args.append('--measure_cpu_costs')
-        extra_args.append('--disable_auto_set_flakes')
 
     all_jobs = _create_test_jobs(extra_args=extra_args, inner_jobs=args.inner_jobs) + \
                _create_portability_test_jobs(extra_args=extra_args, inner_jobs=args.inner_jobs)