Add a shard for unit_tests on Mac10.15-Tests(dbg)

since it is timing out with one shard.

Bug:1265051

Change-Id: I534808f581608da0be058125cb08b30de46eeb96
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3251470
Reviewed-by: Erik Staab <[email protected]>
Commit-Queue: Lindsay Pasricha <[email protected]>
Cr-Commit-Position: refs/heads/main@{#937006}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index 97651f0..95244fce 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -673,6 +673,21 @@
           '--test-launcher-filter-file=../../testing/buildbot/filters/mac.mac-rel.browser_tests.filter',
         ],
       },
+      'Mac10.15 Tests (dbg)': {
+        # crbug.com/1042757
+        'swarming': {
+          'dimension_sets': [
+            {
+              # These shards are liable to time out when running on macmini7,1.
+              'cores': '8|12',
+            }
+          ],
+        },
+        # crbug.com/1196416
+        'args': [
+          '--test-launcher-filter-file=../../testing/buildbot/filters/mac.mac-rel.browser_tests.filter',
+        ],
+      },
       'ToTWin(dbg)': {
         'swarming': {
           'shards': 20,
@@ -2989,6 +3004,11 @@
           '--test-launcher-filter-file=../../testing/buildbot/filters/ozone-linux.unit_tests_wayland.filter',
         ],
       },
+      'Mac10.15 Tests (dbg)': {
+        'swarming': {
+          'shards': 2,
+        },
+      },
       'ToTLinuxASan': {
         'swarming': {
           'shards': 2,