[llvm] [SPIR-V] Add SPIRV to LLVM_ALL_TARGETS (reapply) (PR #123733)

[Nikita Popov via llvm-commits]

nikic wrote:

It looks like parseSPIRVCommandLineOptions is calling cl::ParseCommandLineOptions. This is not legal, as the function isn't thread-safe. (Unless you intended SPIRVTranslateModule to not be thread-safe? In which case the tests can't be executed in paralle.)

https://github.com/llvm/llvm-project/pull/123733