True integer types don't support MSAA, so the blitter never had support
for MSAA on true integer types. In Vulkan, VK_FORMAT_S8_UINT is a UINT
format, so it's considered a true integer type, but it must still support
MSAA.
Added support for MSAA on true integer types in the blitter so fix all
related tests with SwANGLE:
dEQP-GLES3.functional.depth_stencil_clear.*
dEQP-GLES3.functional.fragment_ops.*
dEQP-GLES3.functional.rasterizer_discard.*
Bug: angleproject:4044
Change-Id: I8e04f434f0f671999aaef23cf24cc6684fd0fc16
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/37548
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
