Treat it as a 2D array image by setting the second coordinate to 0 and
assigning the layer coordinate to the third.

Bug: b/129523279
Test: dEQP-VK.pipeline.image.*
Test: dEQP-VK.pipeline.sampler.*
Change-Id: I82e9a8081c2b7d7a2f62ffc016b860925bd853ad
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/30708
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>