[Fuchsia] Sharding for browser tests on fuchsia-code-coverage

Need to shard these tests due to OOM concerns.
Will add ~5 minutes of bot time per code coverage builder run

Change-Id: Ie50005ddbdb544ec3dc32fbabacc82f59b4ac291
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2816006
Auto-Submit: Chong Gu <[email protected]>
Reviewed-by: John Chen <[email protected]>
Commit-Queue: John Chen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#870843}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index 906be65..d5c8361 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -1575,6 +1575,13 @@
     ],
   },
   'headless_browsertests': {
+    'modifications': {
+      'fuchsia-code-coverage': {
+        'swarming': {
+          'shards': 3,
+        },
+      },
+    },
     'remove_from': [
       'CrWinAsan(dll)', # https://crbug.com/935598
     ],
@@ -2798,6 +2805,15 @@
       'linux-chromeos-dbg',  # https://crbug.com/859307
     ],
   },
+  'web_engine_browsertests': {
+    'modifications': {
+      'fuchsia-code-coverage': {
+        'swarming': {
+          'shards': 3,
+        },
+      },
+    },
+  },
   'webdriver_tests_suite': {
     'remove_from': [
       'Linux Tests',  # https://crbug.com/929689, https://crbug.com/936557