[analyzer] suppress nullability inference from a macro when result is used in another macro

The current code used to not suppress the report, if the dereference was
performed in a macro, assuming it is that same macro.
However, the assumption might not be correct, and XNU has quite a bit of
code where dereference is actually performed in a different macro.

As the code uses macro name and not a unique identifier it might be fragile,
but in a worst-case scenario we would simply emit an extra diagnostic.

rdar://36160245

Differential Revision: https://reviews.llvm.org/D41749

llvm-svn: 322149