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/compiler/test/spies.ts

@@ -8,7 +8,7 @@
 
 import {ResourceLoader} from '@angular/compiler/src/resource_loader';
 
-import {SpyObject, proxy} from '@angular/core/testing/testing_internal';
+import {SpyObject} from '@angular/core/testing/testing_internal';
 
 export class SpyResourceLoader extends SpyObject {
   constructor() { super(ResourceLoader); }