chore(lint): remove unused imports (#11923)

This was done automatically by tslint, which can now fix issues it finds.
The fixer is still pending in PR https://github.com/palantir/tslint/pull/1568
Also I have a local bugfix for https://github.com/palantir/tslint/issues/1569
which causes too many imports to be deleted.

modules/@angular/common/test/directives/ng_class_spec.ts

@@ -8,7 +8,7 @@
 
 import {Component} from '@angular/core';
 import {ComponentFixture, TestBed, async} from '@angular/core/testing';
-import {beforeEach, ddescribe, describe, expect, iit, inject, it, xdescribe, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
 export function main() {
   describe('binding to CSS class list', () => {

modules/@angular/common/test/localization_spec.ts

@@ -8,7 +8,7 @@
 
 import {LOCALE_ID} from '@angular/core';
 import {TestBed} from '@angular/core/testing';
-import {AsyncTestCompleter, afterEach, beforeEach, ddescribe, describe, iit, inject, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, inject, it} from '@angular/core/testing/testing_internal';
 import {expect} from '@angular/platform-browser/testing/matchers';
 
 import {NgLocaleLocalization, NgLocalization, getPluralCategory} from '../src/localization';

modules/@angular/common/test/pipes/async_pipe_spec.ts

@@ -8,7 +8,7 @@
 
 import {AsyncPipe} from '@angular/common';
 import {WrappedValue} from '@angular/core';
-import {AsyncTestCompleter, afterEach, beforeEach, ddescribe, describe, expect, iit, inject, it, xit} from '@angular/core/testing/testing_internal';
+import {AsyncTestCompleter, beforeEach, describe, expect, inject, it} from '@angular/core/testing/testing_internal';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {browserDetection} from '@angular/platform-browser/testing/browser_util';
 

modules/@angular/common/test/pipes/date_pipe_spec.ts

@@ -8,7 +8,7 @@
 
 import {DatePipe} from '@angular/common';
 import {PipeResolver} from '@angular/compiler/src/pipe_resolver';
-import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 import {browserDetection} from '@angular/platform-browser/testing/browser_util';
 
 import {DateWrapper} from '../../src/facade/lang';

modules/@angular/common/test/pipes/i18n_plural_pipe_spec.ts

@@ -8,7 +8,7 @@
 
 import {I18nPluralPipe, NgLocalization} from '@angular/common';
 import {PipeResolver} from '@angular/compiler/src/pipe_resolver';
-import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
 export function main() {
   describe('I18nPluralPipe', () => {

modules/@angular/common/test/pipes/i18n_select_pipe_spec.ts

@@ -8,7 +8,7 @@
 
 import {I18nSelectPipe} from '@angular/common';
 import {PipeResolver} from '@angular/compiler/src/pipe_resolver';
-import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
 export function main() {
   describe('I18nSelectPipe', () => {

modules/@angular/common/test/pipes/lowercase_pipe_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import {LowerCasePipe} from '@angular/common';
-import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
 export function main() {
   describe('LowerCasePipe', () => {

modules/@angular/common/test/pipes/number_pipe_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import {CurrencyPipe, DecimalPipe, PercentPipe} from '@angular/common';
-import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 import {browserDetection} from '@angular/platform-browser/testing/browser_util';
 
 export function main() {

modules/@angular/common/test/pipes/slice_pipe_spec.ts

@@ -9,7 +9,6 @@
 import {CommonModule, SlicePipe} from '@angular/common';
 import {Component} from '@angular/core';
 import {TestBed, async} from '@angular/core/testing';
-import {browserDetection} from '@angular/platform-browser/testing/browser_util';
 import {expect} from '@angular/platform-browser/testing/matchers';
 
 export function main() {

modules/@angular/common/test/pipes/uppercase_pipe_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import {UpperCasePipe} from '@angular/common';
-import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 
 export function main() {
   describe('UpperCasePipe', () => {

modules/@angular/common/test/spies.ts

@@ -7,7 +7,7 @@
  */
 
 import {ChangeDetectorRef} from '@angular/core/src/change_detection/change_detector_ref';
-import {SpyObject, proxy} from '@angular/core/testing/testing_internal';
+import {SpyObject} from '@angular/core/testing/testing_internal';
 
 export class SpyChangeDetectorRef extends SpyObject {
   constructor() {