Fix --render-test-output-dir to work in TestSuite. https://crrev.com/c/3956937 introduced the issue where this flag is consumed by ANGLEPerfTestArgs.cpp logic which runs before the TestSuite constructor and removes the flag so we end up with an empty mTestArtifactDirectory in TestSuite. Bug: angleproject:7755 Change-Id: Ic32d3a2ddceca7842a0aebe5a1e40cbedaedf2eb Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4097325 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Roman Lavrov <romanl@google.com>