message: refactor(core): remove unused imports
  This commit removes some unused imports from the spec files.
  PR Close
diff: import {ResourceLoader, UrlResolver} from '@angular/compiler';
  import {MockResourceLoader} from '@angular/compiler/testing';
  -import {AfterContentChecked, AfterContentInit, AfterViewChecked, AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, ContentChild, DebugElement, Directive, DoCheck, EventEmitter, HostBinding, Inject, Injectable, Input, OnChanges, OnDestroy, OnInit, Output, Pipe, PipeTransform, Provider, RendererFactory2, RendererType2, SimpleChange, SimpleChanges, TemplateRef, Type, ViewChild, ViewContainerRef, WrappedValue} from '@angular/core';
  +import {AfterContentChecked, AfterContentInit, AfterViewChecked, AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, ContentChild, DebugElement, Directive, DoCheck, EventEmitter, HostBinding, Injectable, Input, OnChanges, OnDestroy, OnInit, Output, Pipe, PipeTransform, Provider, RendererFactory2, RendererType2, SimpleChange, SimpleChanges, TemplateRef, Type, ViewChild, ViewContainerRef, WrappedValue} from '@angular/core';
  import {ComponentFixture, fakeAsync, TestBed} from '@angular/core/testing';
  import {By} from '@angular/platform-browser/src/dom/debug/by';
  import {isTextNode} from '@angular/platform-browser/testing/src/browser_util';
  