Add GPU bots to the default set of try jobs in ui/gl/ and gpu/.

R=kbr@chromium.org, piman@chromium.org, piman
BUG=270918

Review URL: https://codereview.chromium.org/151593002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248541 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248541