1. Copy the code from src/tests/third_party/gpu_test_expectations to
src/test/test_expectations, rename .cc files to .cpp.  Put these in a new
static library and update dEQP to link against it in src/tests/BUILD.gn.
2. Merge the code in angle_config.h into the rest of the expectations parser,
this code was added so that the rest of the parser would compile in ANGLE's
tree with minimal modification.

Still need to follow up with the third step to close the issue.

Bug: angleproject:2677
Change-Id: Icf09b4eeed83a6d09b1964ad2adcfa85cabb4b63
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1536312
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>