Make GLES 1 tests use ANGLE EGL headers. This will allow us to more easily support a different test target topology for the standalone test harness that uses an intermediate source_set. Also it's better in the long run to only have to worry about one set of EGL headers. Bug: angleproject:3162 Change-Id: I738dbb68df1abc0c0569748e18d6826914d90a52 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2233399 Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>