fix(Scope): ensure that isolate scopes use the main evalAsync queue

Previously any $evalAsync task scheduled from a isolate scope or a child of an isolate scope
would never execute because we never flushed this queue

src/ng/rootScope.js

@@ -165,6 +165,8 @@ function $RootScopeProvider(){
         if (isolate) {
           child = new Scope();
           child.$root = this.$root;
+          // ensure that there is just one async queue per $rootScope and it's children
+          child.$$asyncQueue = this.$$asyncQueue;
         } else {
           Child = function() {}; // should be anonymous; This is so that when the minifier munges
             // the name it does not become random set of chars. These will then show up as class

test/ng/rootScopeSpec.js

@@ -692,6 +692,19 @@ describe('Scope', function() {
       expect($rootScope.log).toBe('12');
     }));
 
+
+    it('should operate only with a single queue across all child and isolate scopes', inject(function($rootScope) {
+      var childScope = $rootScope.$new();
+      var isolateScope = $rootScope.$new(true);
+
+      $rootScope.$evalAsync('rootExpression');
+      childScope.$evalAsync('childExpression');
+      isolateScope.$evalAsync('isolateExpression');
+
+      expect(childScope.$$asyncQueue).toBe($rootScope.$$asyncQueue);
+      expect(isolateScope.$$asyncQueue).toBe($rootScope.$$asyncQueue);
+      expect($rootScope.$$asyncQueue).toEqual(['rootExpression', 'childExpression', 'isolateExpression']);
+    }));
   });