refactor(facade): Remove most of StringMapWrapper facade. (#12022)

This change mostly automated by
12012b07a2
with some manual fixes.

modules/@angular/compiler-cli/test/reflector_host_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {beforeEach, ddescribe, describe, expect, iit, it} from '@angular/core/testing/testing_internal';
+import {beforeEach, describe, expect, it} from '@angular/core/testing/testing_internal';
 import * as ts from 'typescript';
 
 import {ReflectorHost} from '../src/reflector_host';