fix(testing): remove deprecated testing APIs (#9923)

See https://github.com/angular/angular/blob/master/CHANGELOG.md for
prior deprecation and how to update.

modules/@angular/compiler/test/selector_spec.ts

@@ -8,7 +8,6 @@
 
 import {SelectorMatcher} from '@angular/compiler/src/selector';
 import {CssSelector} from '@angular/compiler/src/selector';
-import {beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {el} from '@angular/platform-browser/testing/browser_util';