fix(@angular-devkit/core): remove circular dependencies

Author: hansl

packages/angular_devkit/core/src/virtual-fs/host/record.ts

@@ -13,13 +13,13 @@ import {
   throwError,
 } from 'rxjs';
 import { concatMap, map, reduce, switchMap, toArray } from 'rxjs/operators';
-import { Path, PathFragment } from '..';
 import {
   FileAlreadyExistException,
   FileDoesNotExistException,
   PathIsDirectoryException,
   UnknownException,
-} from '../..';
+} from '../../exception';
+import { Path, PathFragment } from '../path';
 import {
   FileBuffer,
   Host,

packages/angular_devkit/core/src/virtual-fs/host/test.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import { Observable } from 'rxjs';
-import { Path, join, normalize } from '..';
+import { Path, join, normalize } from '../path';
 import { fileBufferToString, stringToFileBuffer } from './buffer';
 import { FileBuffer, HostWatchEvent, HostWatchOptions, Stats } from './interface';
 import { SimpleMemoryHost, SimpleMemoryHostStats } from './memory';