Implement some tests for defaulted constructors. To do this I had to
suppress an error we were previously emitting on valid union code.

llvm-svn: 131440
diff --git a/clang/test/SemaCXX/default-constructor-initializers.cpp b/clang/test/SemaCXX/default-constructor-initializers.cpp
index 9da8556..e783f49 100644
--- a/clang/test/SemaCXX/default-constructor-initializers.cpp
+++ b/clang/test/SemaCXX/default-constructor-initializers.cpp
@@ -59,3 +59,10 @@
   struct S { const int x; ~S(); };
   const S arr[2] = { { 42 } };
 }
+
+// This is valid
+union U {
+  const int i;
+  float f;
+};
+U u;