fix($compile): use createMap() for $$observe listeners when initialized from attr interpolation

This reverts commit 8e28bb4.

Author: lgalfaso

src/ng/compile.js

@@ -2355,7 +2355,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
         compile: function() {
             return {
               pre: function attrInterpolatePreLinkFn(scope, element, attr) {
-                var $$observers = (attr.$$observers || (attr.$$observers = createMap()));
+                var $$observers = (attr.$$observers || (attr.$$observers = {}));
 
                 if (EVENT_HANDLER_ATTR_REGEXP.test(name)) {
                   throw $compileMinErr('nodomevents',

test/ng/compileSpec.js

@@ -3218,23 +3218,6 @@ describe('$compile', function() {
       });
     });
 
-    it('should be able to interpolate attribute names which are present in Object.prototype', function() {
-      var attrs;
-      module(function() {
-        directive('attrExposer', valueFn({
-          link: function($scope, $element, $attrs) {
-            attrs = $attrs;
-          }
-        }));
-      });
-      inject(function($compile, $rootScope) {
-        $compile('<div attr-exposer to-string="{{1 + 1}}"  has-own-property="{{1 + 1}}">')($rootScope);
-        $rootScope.$apply();
-        expect(attrs.toString).toBe('2');
-        expect(attrs.hasOwnProperty).toBe('2');
-      });
-    });
-
 
     describe('bind-once', function() {