Add support for single element vector{load|store} lowering to SPIR-V.
Since, SPIR-V converts single element vector to scalars, it needs
special attention for vector{load|store} lowering to spirv{load|store}.
Add support for single element vector{load|store} lowering to SPIR-V.
Since, SPIR-V converts single element vector to scalars, it needs
special attention for vector{load|store} lowering to spirv{load|store}.