Add DILocation pointing to the local variable declaration site to every MSan/KMSAN hook that poisons that local variable.
The DILocation is picked from one of the debug intrinsics referencing the corresponding alloca instruction and being:
- either a llvm.dbg.declare intrinsic;
- or a llvm.dbg.addr intrinsic;
- or a llvm.dbg.value intrinsic with DW_OP_deref tag.