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>