Get rid of SWARM_TESTS hardcoded list in master.
Get rid of SWARM_TESTS hardcoded list in master.

The last user was the Isolate builders on the Swarming canary master. It is not
necessary.

R=stip@chromium.org
BUG=

Review URL: https://codereview.chromium.org/171223002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@251909 0039d316-1c4b-4281-b951-d872f2087c98

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