Fix a couple bugs:

- NonLoc::MakeVal() would use sizeof(unsigned) (literally) instead of consulting
  ASTContext for the size (in bits) of 'int'. While it worked, it was a
  conflation of concepts and using ASTContext.IntTy is 100% correct.
- RegionStore::getSizeInElements() no longer assumes that a VarRegion has the
  type "ConstantArray", and handles the case when uses use ordinary variables
  as if they were arrays.
- Fixed ElementRegion::getRValueType() to just return the rvalue type of its
  "array region" in the case the array didn't have ArrayType.
- All of this fixes <rdar://problem/6541136>

llvm-svn: 63347