TestRunner: Fix test result handling. The bots expect us to explicitly label "is_unexpected" for all unexpected results (e.g. failures). Also they construct a test filter from our test names so our result names have to match the tests exactly. That means removing prefixes like we have for the test suite name. Bug: angleproject:3162 Change-Id: I1a02ff8e26545b10a8829a3ee47be91f7459aa65 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2345028 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>