Run browser_tests on ubsan bots.

Not clear why it wasn't running, and network_service_browser_tests,
not_site_per_process_browser_tests, viz_browser_tests already all run and
pass -- and what's better than running browser_tests three times? Running it
four times, so add vanilla browser_tests too.

Bug: 843511
Change-Id: I682375c0c4a5a673a0e5410452d5560cad3ccebd
Reviewed-on: https://chromium-review.googlesource.com/1117019
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570771}

testing/buildbot/chromium.clang.json

@@ -15437,6 +15437,13 @@
         },
         "test": "boringssl_ssl_tests"
       },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 10
+        },
+        "test": "browser_tests"
+      },
       {
         "args": [
           "--enable-features=NetworkService",
@@ -23625,6 +23632,13 @@
         },
         "test": "boringssl_ssl_tests"
       },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 10
+        },
+        "test": "browser_tests"
+      },
       {
         "args": [
           "--enable-features=NetworkService",

testing/buildbot/test_suite_exceptions.pyl

@@ -189,10 +189,8 @@
       # chromium.clang
       'CrWinAsanCov',
       'linux-win_cross-rel',
-      'ToTLinuxUBSanVptr',
       'ToTMac', # https://crbug.com/828031
       'ToTMacASan', # https://crbug.com/828031
-      'UBSanVptr Linux',
       # chromium.fyi
       'Chromium Mac 10.13', # https://crbug.com/828031
       'Out of Process Profiling Mac', # https://crbug.com/828031