Downgrade the invalid offsetof error to a warning.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70634 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/offsetof.cpp b/test/SemaCXX/offsetof.cpp
index 726dc7e..c8a3d3d 100644
--- a/test/SemaCXX/offsetof.cpp
+++ b/test/SemaCXX/offsetof.cpp
@@ -10,6 +10,6 @@
 };
 
 void f() {
-  int i = __builtin_offsetof(P, fieldThatPointsToANonPODType.m); // expected-error{{offset of on non-POD type 'struct P'}}
+  int i = __builtin_offsetof(P, fieldThatPointsToANonPODType.m); // expected-warning{{offset of on non-POD type 'struct P'}}
 }