Remove builders from vm slaves that run out of space.
Remove builders from vm slaves that run out of space.

This previous change added ccompute bots to share the load of the vm slaves:
https://codereview.chromium.org/26925002/
Now we can remove builders from the vm slaves so they don't run out of space.

BUG=302063

Review URL: https://codereview.chromium.org/26584007

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@229226 0039d316-1c4b-4281-b951-d872f2087c98

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