clang/lib/Analysis/CFG.cpp: Fix memory leak since r153297.

evaluateAsBooleanConditionNoCache(S) might update the map and invalidate the iterator.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153406 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed