Add a number of glMemoryBarrier tests Bug: angleproject:5070 Change-Id: I835a4e936cb50d3f4b1187bebbe1d1adc49d0b52 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2689366 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>