Run the swarm steps if there is no testfilter specified.
Run the swarm steps if there is no testfilter specified.

R=maruel@chromium.org
BUG=


Review URL: https://chromiumcodereview.appspot.com/12317068

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@184109 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build