[analyzer] When looking for a known class, only traverse the hierarchy once.

This has a small hit in the case where only one class is interesting
(NilArgChecker) but is a big improvement when looking for one of several
interesting classes (VariadicMethodTypeChecker), in which the most common
case is that there is no match.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158318 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed