[OPENMP][DEBUG] Set proper address space info if required by target.

[OPENMP][DEBUG] Set proper address space info if required by target.

Arguments, passed to the outlined function, must have correct address
space info for proper Debug info support. Patch sets global address
space for arguments that are mapped and passed by reference.

Also, cuda-gdb does not handle reference types correctly, so reference
arguments are represented as pointers.

llvm-svn: 310387