Reshard browser_tests on Linux MSan Tests to avoid a timeout

browser_tests is occasionally going over the time limit. Increase
the shard count to allow testing to finish in time

Bug: 1356048
Change-Id: Ibee80047f00aa3393c9dc1c2b61a54b54e06b534
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3893236
Reviewed-by: Jiewei Qian <[email protected]>
Commit-Queue: Struan Shrimpton <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1046399}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index ea5266ba..9b40995 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -949,6 +949,11 @@
           '--test-launcher-filter-file=../../testing/buildbot/filters/chromeos.msan.browser_tests.oobe_negative.filter',
         ],
       },
+      'Linux MSan Tests': {
+        'swarming': {
+          'shards': 12,
+        },
+      },
       'Linux Tests': {
         'swarming': {
           'quickrun_shards': 15,