Convert swarm_triggered to OS specific builder.

The try server is splitting up these builders so the CQ has to
adapt accordingly.

Reenable linux_swarm_triggered.

TBR=xusydoc@chromium.org
BUG=

Review URL: https://codereview.chromium.org/24633002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/commit-queue@230165 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed