Added ability to generate correct debug info data about the variable
address class. Currently, for all the locals and globals the default
values are used, ADDR_local_space(6) for locals and ADDR_global_space(5)
for globals. The values are taken from the table in
https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf. We need to emit correct data for address classes of, at least, shared and constant globals. Currently, all these variables are treated by the cuda-gdb debugger as the variables in the global address space and, thus, it require manual data type casting.