Summary:
This should enable test pilot to skip broken/flakey tests.

The `--tag-new-tests` flag is only appropriate for code that has been
landed on master and is used by the FB infra to classify new tests
appropriately.

For continuous builds we use a test collection with different parameters
from the normal developer facing flow so that the infra can re-assess
their status and enable/disable high-signal/noisy tests.

Depends: D15495344

Reviewed By: Ben0mega

Differential Revision: D15500955

fbshipit-source-id: f3b7976cec6a5cf70f5d128b38bde11620b26918