Fix 8-bit storage nearly always using the

UniformAndStorageBuffer8BitAccess capability.

When using the 8-bit storage extension it basically always used the
`UniformAndStorageBuffer8BitAccess` capability, even in cases where it
wasn't required. For instance if we are targeting Vulkan 1.1 (SPIR-V 1.3
or higher), and we are only using 8-bit types in an SSBO, we only need
the `StorageBuffer8BitAccess` capability.

I fixed this by enabling storage buffer use in Vulkan 1.1 / SPIR-V 1.3
or higher, and then changing the logic to match.

I also added some tests that will output different capabilities when run
on Vulkan 1.0 and 1.1, thus they are added twice to the test list (one
for each version).

Fixes #1539

Test/baseResults/spv.8bitstorage-uint.frag.out

@@ -4,7 +4,6 @@ spv.8bitstorage-uint.frag
 // Id's are bound by 173
 
                               Capability Shader
-                              Capability CapabilityStorageBuffer8BitAccess
                               Capability CapabilityUniformAndStorageBuffer8BitAccess
                               Extension  "SPV_KHR_8bit_storage"
                1:             ExtInstImport  "GLSL.std.450"