Add master flag to tryjob query
Add master flag to tryjob query

This means the backend will also return images that are in
the master baseline. For now the flag has to be added manually (no UI).

Bug: skia:
Change-Id: Ie88a85170f786cec5e0b890bb1898ebf8433827a
Reviewed-on: https://skia-review.googlesource.com/107945
Reviewed-by: Kevin Lubick <7cdab2cfab351f23814786ba39716e90eed69047@google.com>
Commit-Queue: Stephan Altmueller <43343ec95731c0e8daa7359daf7f2f3935582b24@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot