The tests RobustClientMemoryTest.* now all pass.

Bug: angleproject:6108
Change-Id: I980c1fd9e065cb5c4ed575770f86e09faeb19d4c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2988685
Commit-Queue: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>