Allow specifying GPU config on expectation check. When we load the expectations we can now specify the config at a later point. This will make it easier to run test suites that use multiple APIs, like angle_end2end_tests. We can instead specify the config when we check the expectation. Bug: angleproject:5951 Change-Id: I9607db093e4a459550a7cd6864b17adfa55e17f2 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2892273 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>