Full vector and fully specified vector swizzle stores are not affected by this change, only partial swizzles ie swizzles with fewer components than the vector being stored to.
Previously the vector being stored to loaded and any components not specified in the swizzle were used to create a full store to the vector.
While this change generates more SPIR-V instructions, it is necessary for correctness.
Fixes#2518.
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
