This PR shifts from using the LLVM OpenMP enumerator bit flags to an
OpenMP dialect specific enumerator. This allows us to better represent
map types that wouldn't be of interest to the LLVM backend and runtime
in the dialect.
Primarily things like
ref_ptr/ref_ptee/ref_ptr_ptee/atach_none/attach_always/attach_auto which
are of interest to the compiler for certrain transformations (primarily
in the FIR transformation passes dealing with mapping), but the runtime
has no need to know about them. It also means if another OpenMP
implementation comes along they won't need to stick to the same bit flag
system LLVM chose/do leg work to address it.
