[analyzer] Implement pointer arithmetic on constants

Patch by: Rafael Stahl!

Differential Revision: https://reviews.llvm.org/D37478

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@315296 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit f8ba2666e1ba6d8717740ae3673cddcf416e623f)
2 files changed