Clover: SPIR-V support improvements
The main feature is to list all supported SPIR-V versions so that we can make use of the new SPIRV-LLVM-Translator API to request a target SPIR-V version.
By bumping the requested SPIRV-LLVM-Translator version, we also ensure that no one will run into using a 0.2.1 version that has an old version of the API, resulting in compilation failures.