Invoke the standalone test harness runner. Previously we were still calling GoogleTest directly. This change switches the test main funtions to call the standalone harness. Only affects standalone and shouldn't affect the tests in Chromium or on the current test setup. Bug: angleproject:3162 Change-Id: Ia5a5a73d47c0b47b4df8f54cd6df71da2d878847 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1998661 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>