Work around internal compiler error on MSVC 2015 Update 3 x86

Change-Id: If62418e29741cef6790690eba2b4c890cd8fcaee
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

chromium/third_party/skia/src/gpu/GrSwizzle.h

@@ -95,9 +95,10 @@ public:
             case 3:
                 return AAAA();
             default:
-                SkFAIL("Mod is broken?!?");
-                return RGBA();
+                break;
         }
+        SkFAIL("Mod is broken?!?");
+        return RGBA();
     }
 
 private: