Swarm all tests running on ClangToTLinux tester that were swarmed on at least one other bot already.

testing/buildbot/chromium.chromiumos.json

Index: testing/buildbot/chromium.chromiumos.json
diff --git a/testing/buildbot/chromium.chromiumos.json b/testing/buildbot/chromium.chromiumos.json
index 2cfe693029d896db190e9da7bad94561399c01fb..5909856d3af0bd4965ea4146bfce5f8c8c46f63f 100644
--- a/testing/buildbot/chromium.chromiumos.json
+++ b/testing/buildbot/chromium.chromiumos.json
@@ -204,6 +204,9 @@
         "test": "midi_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_helper_nonsfi_unittests"
       },
       {
@@ -503,6 +506,9 @@
         "test": "midi_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_helper_nonsfi_unittests"
       },
       {
@@ -798,6 +804,9 @@
         "test": "midi_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_helper_nonsfi_unittests"
       },
       {