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

[Romaric Jodin via cfe-commits]

rjodinchr 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?

I don't know why we have `spir` and not `spirv` in the triple used by `clspv`. @alan-baker might know more about that.

But for the libclc backend, I don't foresee `clspv` being able to use the SPIR-V backend soon, so it would be better to keep something specific to `clspv` for now.

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