Don't run find_isolated_tests on tester bots.
Don't run find_isolated_tests on tester bots.

It should only run on builder or builder_tester, as those are the ones with a build directory and which generate the swarming hashes.

BUG=414808
TBR=phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/595223002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@292108 0039d316-1c4b-4281-b951-d872f2087c98

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