[analyzer; alternate arrows] don't increment the path iterator when we just...

[analyzer; alternate arrows] don't increment the path iterator when we just deleted the next iterator.

This is an optimization.  It is possible that by deleting the next
edge we will pattern match again at the current spot.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181256 91177308-0d34-0410-b5e6-96231b3b80d8