Shard net_unittests on ToTLinuxASan 16 ways to match memory bot

BUG=chromium:794372
[email protected]
NOTRY=True

Change-Id: Iaef5d1b0e4fcb155d90de714187e16496fdfdee1
Reviewed-on: https://chromium-review.googlesource.com/1015847
Commit-Queue: Reid Kleckner <[email protected]>
Reviewed-by: Nico Weber <[email protected]>
Cr-Commit-Position: refs/heads/master@{#551732}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index cb82aae..d96f756 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -2307,8 +2307,9 @@
       },
       # chromium.clang
       'ToTLinuxASan': {
+        # TODO(crbug.com/794372): net_unittests is slow under ASan.
         'swarming': {
-          'shards': 4,
+          'shards': 16,
         },
       },
       # chromium.memory