Look through chains of 'x = y = z' when employing silencing heuristics in the DeadStoresChecker.

Fixes <rdar://problem/11185138>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154040 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed