[Fuchsia] Double shards for web_engine_browsertests code coverage

These tests are still running into OOM issues around 70%
of the way, so double the shards used.

Change-Id: If55e285b33bbc61b1286c2cdc0528d6be5fe95ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3032047
Auto-Submit: Chong Gu <[email protected]>
Reviewed-by: Brian Sheedy <[email protected]>
Commit-Queue: Brian Sheedy <[email protected]>
Cr-Commit-Position: refs/heads/master@{#903114}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index d929794..c96a9ef0 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -3106,7 +3106,7 @@
     'modifications': {
       'fuchsia-code-coverage': {
         'swarming': {
-          'shards': 14,
+          'shards': 28,
         },
       },
     },