refactor(interpolate): remove redundant $watchGroup param

Closes angular#11021

Author: marcin-wosinek

src/ng/interpolate.js

@@ -286,15 +286,15 @@ function $InterpolateProvider() {
           // all of these properties are undocumented for now
           exp: text, //just for compatibility with regular watchers created via $watch
           expressions: expressions,
-          $$watchDelegate: function(scope, listener, objectEquality) {
+          $$watchDelegate: function(scope, listener) {
             var lastValue;
             return scope.$watchGroup(parseFns, function interpolateFnWatcher(values, oldValues) {
               var currValue = compute(values);
               if (isFunction(listener)) {
                 listener.call(this, currValue, values !== oldValues ? lastValue : currValue, scope);
               }
               lastValue = currValue;
-            }, objectEquality);
+            });
           }
         });
       }