[libclc] [libclc] Fix using normalized triple for the directory name (PR #194607)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

@rjodinchr I'm looking into replacing the `clspv` path and I'd like to know the significance of `spir--` and `spirv`. Is there a point where we can transition to fully using the SPIR-V backend?

https://github.com/llvm/llvm-project/pull/194607