chore(imports): don't import ExceptionHandler from facade (#10620)

This lets us skip src/facade/exception* when compiling modules other than core.
It prevents having many conflicting declarations

modules/@angular/http/src/static_response.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {BaseException} from '../src/facade/exceptions';
+import {BaseException} from '@angular/core';
 import {Json, isString} from '../src/facade/lang';
 
 import {ResponseOptions} from './base_response_options';