With robustResourceInit and the hadling of the serialization
of uninitialized attachments these tests pass now.

Bug: None
Change-Id: I86af69f7e928d32570fde90b106e34d21617f0f8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2982547Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Gert Wollny <gert.wollny@collabora.com>