[analyzer] PR43551: Do not dereferce void* in UndefOrNullArgVisitor.

Patch by Kristóf Umann!

Differential Revision: https://reviews.llvm.org/D68591

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@375329 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed