[ios] ios14 tests on chromium.tests.ios14

iOS14 tests to execute on chromium.tests.ios14.

Bug: 1101531
Change-Id: I8fee379d472ed05c73eeed75b8bf6f50b83a1694
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2295788Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Commit-Queue: Jeff Yoon <jeffyoon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789273}

testing/buildbot/mixins.pyl

@@ -207,6 +207,13 @@
       'service_account': 'chromium-tester@chops-service-accounts.iam.gserviceaccount.com',
     },
   },
+  'chromium-tests-ios14': {
+    'swarming': {
+      'dimensions': {
+        'pool': 'chromium.tests.ios14',
+      },
+    },
+  },
   # TODO(crbug.com/1057152): Add this mixin unconditionally for all CrOS device
   # tests.
   'cros_device_flash': {

testing/buildbot/waterfalls.pyl

@@ -2104,6 +2104,7 @@
           'all',
         ],
         'mixins': [
+          'chromium-tests-ios14',
           'mac_10.15',
           'mac_toolchain',
           'out_dir_arg',
@@ -2120,6 +2121,7 @@
           'all',
         ],
         'mixins': [
+          'chromium-tests-ios14',
           'mac_10.15',
           'mac_toolchain',
           'out_dir_arg',