cleanup: move DomAdapter from angular2/core into angular2/platform/common_dom

BREAKING CHANGE

Before

import {DomAdapter} from 'angular2/core';

After

import {DomAdapter} from 'angular2/platform/common_dom';

Closes #5370

modules/angular2/test/common/directives/ng_if_spec.ts

@@ -12,7 +12,7 @@ import {
   xit,
 } from 'angular2/testing_internal';
 
-import {DOM} from 'angular2/src/core/dom/dom_adapter';
+import {DOM} from 'angular2/src/platform/dom/dom_adapter';
 
 import {Component, View} from 'angular2/core';
 import {NgIf} from 'angular2/common';

modules/angular2/test/common/directives/ng_style_spec.ts

@@ -18,7 +18,7 @@ import {StringMapWrapper} from 'angular2/src/facade/collection';
 
 import {Component, View} from 'angular2/angular2';
 
-import {DOM} from 'angular2/src/core/dom/dom_adapter';
+import {DOM} from 'angular2/src/platform/dom/dom_adapter';
 import {NgStyle} from 'angular2/src/common/directives/ng_style';
 
 export function main() {

modules/angular2/test/common/directives/non_bindable_spec.ts

@@ -11,7 +11,7 @@ import {
   it,
   xit,
 } from 'angular2/testing_internal';
-import {DOM} from 'angular2/src/core/dom/dom_adapter';
+import {DOM} from 'angular2/src/platform/dom/dom_adapter';
 import {Component, Directive, View} from 'angular2/core';
 import {ElementRef} from 'angular2/src/core/linker/element_ref';
 

modules/angular2/test/common/forms/integration_spec.ts

@@ -18,8 +18,7 @@ import {
   browserDetection
 } from 'angular2/testing_internal';
 
-import {DOM} from 'angular2/src/core/dom/dom_adapter';
-import {Input, Provider, forwardRef} from 'angular2/core';
+import {DOM} from 'angular2/src/platform/dom/dom_adapter';
 import {
   Control,
   ControlGroup,
@@ -34,6 +33,7 @@ import {
   Validators,
   Validator
 } from 'angular2/common';
+import {Input, Provider, forwardRef} from 'angular2/core';
 import {By} from 'angular2/platform/browser';
 import {ListWrapper} from 'angular2/src/facade/collection';
 import {ObservableWrapper} from 'angular2/src/facade/async';

modules/angular2/test/common/pipes/async_pipe_spec.ts

@@ -22,7 +22,7 @@ import {
   PromiseWrapper,
   TimerWrapper
 } from 'angular2/src/facade/async';
-import {DOM} from 'angular2/src/core/dom/dom_adapter';
+import {DOM} from 'angular2/src/platform/dom/dom_adapter';
 
 export function main() {
   describe("AsyncPipe", () => {