See  bug 699242  for motivation ... there's probably a need from time-to-time to run tests on the continuous builders that we can't easily afford to run on the CQ.

Today, you can't just add a test to an existing CQ builder and indicate that that's what you want; if you want something to be waterfall-only you need to either set up a new builder or at least set up a new triggered tester (or add something to an existing triggered tester).

It seems like we should generally be moving away from triggered testers, and so it might be good to figure out how to support the idea of "waterfall-only" test steps in the //testing/buildbot/*.json files.

That said, this should not be the first choice for most tests, since we generally want the CQ coverage to match the waterfall.