Infra: Disabling browser_tests on Mac again

Bug: 1042757
Change-Id: If4096e9641965a410411d35c47ec8d97ae80276a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2657740
Auto-Submit: Gary Tong <gatong@chromium.org>
Commit-Queue: Gary Tong <gatong@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#848328}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index 94b0e5f..1e17a93 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -441,6 +441,7 @@
       'CrWinAsan(dll)', # https://crbug.com/935598
       'linux-win_cross-rel',
       'ToTLinuxTSan',  # https://crbug.com/368525
+      'Mac10.13 Tests', # https://crbug.com/1042757
       'Linux TSan Tests',  # https://crbug.com/368525
       'Win10 Tests x64 (dbg)',
     ],
@@ -510,12 +511,6 @@
           'shards': 30,
         },
       },
-      'Mac10.13 Tests':{
-        'experiment_percentage': 10, # https://crbug.com/1042757
-        'swarming': {
-          'shards': 40,
-        },
-      },
       'Mac10.13 Tests (dbg)': {
         # https://crbug.com/1152770
         'swarming': {