Increase sharding for sync_integration_tests on linux ASAN builder.

The test suite takes 27 minutes to run with only 40 seconds overhead. It's the
slowest test suite on linux_chromium_asan_rel_ng, which causes long cycle times.

Bug: 1028289
Change-Id: Ib82100928d89e29747a8794f62eccc09cf27aae3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1932475
Commit-Queue: Erik Chen <[email protected]>
Commit-Queue: John Budorick <[email protected]>
Auto-Submit: Erik Chen <[email protected]>
Reviewed-by: John Budorick <[email protected]>
Cr-Commit-Position: refs/heads/master@{#718886}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index f087d58..0c4396c 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -1550,6 +1550,12 @@
         },
       },
       # chromium.memory
+      'Linux ASan LSan Tests (1)': {
+        'swarming': {
+          'shards': 4,
+        },
+      },
+      # chromium.memory
       'Linux TSan Tests': {
         'swarming': {
           'shards': 6,