Tweak diagnostic:

  error: no super class declared in @interface for 'XXX'

to be:

  error: 'X' cannot use 'super' because it is a root class

The latter explains what the user actually did wrong.

Fixes: <rdar://problem/8904409>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124074 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaObjC/undef-superclass-1.m b/test/SemaObjC/undef-superclass-1.m
index 0c2594c..c941f82 100644
--- a/test/SemaObjC/undef-superclass-1.m
+++ b/test/SemaObjC/undef-superclass-1.m
@@ -22,7 +22,7 @@
 
 @implementation SUPER
 - (void)dealloc {
-    [super dealloc]; // expected-error {{no super class declared in @interface for 'SUPER'}}
+    [super dealloc]; // expected-error {{'SUPER' cannot use 'super' because it is a root class}}
 }
 @end