Don't clear OverloadCandidateSets on destruction, it has no effect anymore.

And clearing a SmallPtrSet can be an expensive operation.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128081 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Sema/Overload.h

@@ -648,8 +648,6 @@ namespace clang {
     /// \brief Clear out all of the candidates.
     void clear();
 
-    ~OverloadCandidateSet() { clear(); }
-
     /// Find the best viable function on this overload set, if it exists.
     OverloadingResult BestViableFunction(Sema &S, SourceLocation Loc,
                                          OverloadCandidateSet::iterator& Best,