Add regression test for GL bug w.r.t cached programs Bug: angleproject:6073 Change-Id: I22ffabea8a686e2ae615e99607cb557324c23c78 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2976185 Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>