SNORM textures are non-renderable on vanilla ES, which means they're also
non-readable. Use the EXT_render_snorm extension where available, otherwise
skip the test for now.
Bug: dawn:624 dawn:636 dawn:647 dawn:667
Change-Id: Ic50368032d6168060b6b52889b4ba952ce662f02
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/40420
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Stephen White <senorblanco@chromium.org>