Replace a cast with a dyn_cast as suggested by Doug.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72624 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/abstract.cpp b/test/SemaCXX/abstract.cpp
index cf73221..dc764da 100644
--- a/test/SemaCXX/abstract.cpp
+++ b/test/SemaCXX/abstract.cpp
@@ -118,3 +118,11 @@
 	B b;
 }
 
+struct K {
+ int f;
+ virtual ~K();
+};
+
+struct L : public K {
+ void f();
+};