Remove virtual destructor from InstVisitor. This class should never be

used through a base pointer/reference so inproper destruction should
never be an issue. Removing this last virtual function also saves 4
bytes off each InstVisitor instance.

llvm-svn: 13664

llvm/include/llvm/Support/InstVisitor.h

@@ -71,8 +71,6 @@ class AllocationInst;
 
 template<typename SubClass, typename RetTy=void>
 struct InstVisitor {
-  virtual ~InstVisitor() {}           // We are meant to be derived from
-
   //===--------------------------------------------------------------------===//
   // Interface code - This is the public interface of the InstVisitor that you
   // use to visit instructions...