Compat: Fix readonly depth-stencil sampling

[greggman]

It's not entirely clear to me what we should do here. For now, the failing tests are skipped in compat mode

The current compat spec says you can't have 2 different TEXTURE_BINDING views with different settings for the same texture. So you can't view a depth-stencil texture as both an aspect: 'stencil-only' in one view and aspect: 'depth-only' in another view in the same draw call.

You can view them as one or the other in separate draw calls. Should we add a path that uses 2 draw calls? If so, can that be a separate PR?

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[shrekshao]

You can view them as one or the other in separate draw calls. Should we add a path that uses 2 draw calls? If so, can that be a separate PR?

Sounds reasonable.

LGTM

[Kangz]

Whoops I should have thought of compat, thanks for looking into that!