dEQP: Abort gtest run on exception. Prevents massive infra failures when the tests are all broken. This also gives the GoogleTest harness the ability to handle different test result types. Bug: angleproject:2552 Change-Id: Id9832e8557e2ee4e6a248a27729f67a81bf2d830 Reviewed-on: https://chromium-review.googlesource.com/1064014 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>