fix(platform-browser/testing): clean up public api for platform-browser/testing (#9519)

Mostly, removing things that were never intended to be exported publicy.

BREAKING CHANGE:

The following are no longer publicly exported APIs. They were intended as internal
utilities and you should use your own util:

```
browserDetection,
dispatchEvent,
el,
normalizeCSS,
stringifyElement,
expect (and custom matchers for Jasmine)
```

modules/@angular/core/test/animation/active_animations_players_map_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
-import {el} from '@angular/platform-browser/testing';
+import {el} from '@angular/platform-browser/testing/browser_util';
 
 import {ActiveAnimationPlayersMap} from '../../src/animation/active_animation_players_map';
 import {isPresent} from '../../src/facade/lang';

modules/@angular/core/test/animation/animation_style_util_spec.ts

@@ -6,17 +6,11 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
-import {el} from '@angular/platform-browser/testing';
-
 import {FILL_STYLE_FLAG} from '../../src/animation/animation_constants';
 import {AnimationKeyframe} from '../../src/animation/animation_keyframe';
 import * as animationUtils from '../../src/animation/animation_style_util';
 import {AnimationStyles} from '../../src/animation/animation_styles';
 import {AUTO_STYLE} from '../../src/animation/metadata';
-import {isPresent} from '../../src/facade/lang';
-import {fakeAsync, flushMicrotasks} from '../../testing';
-import {MockAnimationPlayer} from '../../testing/animation/mock_animation_player';
 import {AsyncTestCompleter, beforeEach, ddescribe, describe, expect, iit, inject, it, xdescribe, xit} from '../../testing/testing_internal';
 
 export function main() {

modules/@angular/core/test/dom/dom_adapter_spec.ts

@@ -9,7 +9,7 @@
 import {beforeEach, ddescribe, describe, expect, iit, inject, it, xit, beforeEachProviders,} from '@angular/core/testing/testing_internal';
 
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
-import {el, stringifyElement} from '@angular/platform-browser/testing';
+import {el, stringifyElement} from '@angular/platform-browser/testing/browser_util';
 
 export function main() {
   describe('dom adapter', () => {

modules/@angular/core/test/linker/dynamic_component_loader_spec.ts

@@ -18,7 +18,7 @@ import {DOCUMENT} from '@angular/platform-browser/src/dom/dom_tokens';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {BaseException} from '../../src/facade/exceptions';
 import {PromiseWrapper} from '../../src/facade/promise';
-import {el} from '@angular/platform-browser/testing';
+import {el} from '@angular/platform-browser/testing/browser_util';
 
 export function main() {
   describe('DynamicComponentLoader', function() {

modules/@angular/core/test/linker/integration_spec.ts

@@ -36,7 +36,7 @@ import {TemplateRef, TemplateRef_} from '@angular/core/src/linker/template_ref';
 
 import {Renderer} from '@angular/core/src/render';
 import {IS_DART} from '../../src/facade/lang';
-import {el, dispatchEvent} from '@angular/platform-browser/testing';
+import {el, dispatchEvent} from '@angular/platform-browser/testing/browser_util';
 
 const ANCHOR_ELEMENT = /*@ts2dart_const*/ new OpaqueToken('AnchorElement');
 

modules/@angular/core/test/linker/ng_container_integration_spec.ts

@@ -13,7 +13,7 @@ import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {OpaqueToken, ViewMetadata, Component, Directive, AfterContentInit, AfterViewInit, QueryList, ContentChildren, ViewChildren, Input} from '@angular/core';
 import {NgIf} from '@angular/common';
 import {CompilerConfig} from '@angular/compiler';
-import {el} from '@angular/platform-browser/testing';
+import {el} from '@angular/platform-browser/testing/browser_util';
 
 const ANCHOR_ELEMENT = new OpaqueToken('AnchorElement');
 
@@ -216,4 +216,4 @@ class Simple {
 })
 class MyComp {
   ctxBoolProp: boolean = false;
-}
+}

modules/@angular/core/test/linker/security_integration_spec.ts

@@ -14,7 +14,7 @@ import {provide, Injectable, OpaqueToken} from '@angular/core';
 import {CompilerConfig} from '@angular/compiler';
 import {Component, ViewMetadata} from '@angular/core/src/metadata';
 import {IS_DART} from '../../src/facade/lang';
-import {el} from '@angular/platform-browser/testing';
+import {el} from '@angular/platform-browser/testing/browser_util';
 
 import {DomSanitizationService} from '@angular/platform-browser';
 
@@ -240,4 +240,4 @@ function declareTests({useJit}: {useJit: boolean}) {
           });
     });
   });
-}
+}

modules/@angular/core/test/reflection/reflector_spec.ts

@@ -12,7 +12,7 @@ import {Reflector, ReflectionInfo} from '@angular/core/src/reflection/reflection
 import {ReflectionCapabilities} from '@angular/core/src/reflection/reflection_capabilities';
 import {ClassDecorator, ParamDecorator, PropDecorator, classDecorator, paramDecorator, propDecorator, HasGetterAndSetterDecorators} from './reflector_common';
 import {IS_DART} from '../../src/facade/lang';
-import {browserDetection} from '@angular/platform-browser/testing'
+import {browserDetection} from '@angular/platform-browser/testing/browser_util'
 
 class AType {
   value: any /** TODO #9100 */;

modules/@angular/core/test/zone/ng_zone_spec.ts

@@ -14,7 +14,7 @@ import {BaseException} from '../../src/facade/exceptions';
 import {IS_DART, scheduleMicroTask, isPresent} from '../../src/facade/lang';
 import {AsyncTestCompleter} from '@angular/core/testing/testing_internal';
 import {NgZone, NgZoneError} from '@angular/core/src/zone/ng_zone';
-import {browserDetection} from '@angular/platform-browser/testing';
+import {browserDetection} from '@angular/platform-browser/testing/browser_util';
 
 var needsLongerTimers = browserDetection.isSlow || browserDetection.isEdge;
 var resultTimer = 1000;