On iOS GPU family 2 and earlier:
- Allow immutable samplers to be passed to SPIRV-Cross in a format
they can be output as hardcoded constexpr samplers in MSL.
- Validate depth compare samplers are only used as immutable.
MVKMVKPipelineLayout & MVKDescriptorSetLayout can take null MVKCommandEncoder
to perform a validation pass when binding or pushing.
Reduce redundancy by combining SPIRVToMSLConverterContext structs
with compatible SPIRV-Cross structs.
Update MoltenVK version to 1.0.36.
64d7e07243