This finishes our KHR_swapchain v70 implementation.

Test: dEQP-VK.wsi.*
Change-Id: I512e0c086db687ca7ffb8cd5e5375fa7a9d432cd
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/35929Tested-by: Chris Forbes <chrisforbes@google.com>
Kokoro-Presubmit: Chris Forbes <chrisforbes@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>