Teach CIR pointers about address space

[bcardosolopes]

We don't support that yet. A good place to start is to change addressSpace() and addressSpaceInGlobalVar() functions to return true in clang/lib/CIR/CodeGen/UnimplementedFeatureGuarding.h, run ninja check-clang-cir and start working over the found crashes.

(cc: @sommerlukas @sitio-couto)