Add an option to not run compiler in IR2OC (#47633)
I have a case where I'm generating an opaque closure that is only run
once, but LLVM takes 200s to compile it. This adds an option to not
run LLVM in the IR2OC path, which is useful for two things:
1. Getting a handle on the OC without waiting for LLVM to finish,
so we can have it dump out the unoptimized LLVM IR for profiling
purposes.
2. Just actually not running LLVM, since it's probably not worth it.
