[libclc] [libclc] Remove bitcode prepare utility from OpenCL library build (PR #174447)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> > I don't know why this is a property that becomes a module flag
> 
> It's only used in TLI for some strlen optimizations I think. It'd be easy to turn off for OpenCL, and 100% correct to do so I'd say. I don't know if there's a better fix overall.

To rephrase, I do not know why this is emitted a a module flag and not something that's just directly computed from the triple 

https://github.com/llvm/llvm-project/pull/174447