See https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/chromeos-amd64-generic-rel/22250 where a change got in that caused the browser to crash. This made a number of tests correctly fail, but telemetry_unittests took too long to do so. Each test in the suite appears to wait up to 15min for the browser to come up. Since there's 100s of tests, that's a lot of time spent waiting.

eg:
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testOverviewMode failed unexpectedly 924.4219s:
from https://chromium-swarm.appspot.com/task?id=41089d2c2335c010

We should make the suite and its individual tests fail fast if the browser is broken.