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/compiler/test/ml_parser/ast_spec_utils.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 * as html from '../../src/ml_parser/ast';
 import {ParseTreeResult} from '../../src/ml_parser/html_parser';
 import {ParseLocation} from '../../src/parse_util';