fix(@angular-devkit/schematics): fix task executor on Windows

Before we did not denormalize the paths, but were expecting to get paths as options.

Author: hansl

packages/angular_devkit/schematics/tools/workflow/node-workflow.ts

@@ -5,7 +5,7 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import { Path, virtualFs } from '@angular-devkit/core';
+import { Path, getSystemPath, virtualFs } from '@angular-devkit/core';
 import {
   workflow,
 } from '@angular-devkit/schematics';  // tslint:disable-line:no-implicit-dependencies
@@ -42,13 +42,13 @@ export class NodeWorkflow extends workflow.BaseWorkflow {
       {
         allowPackageManagerOverride: true,
         packageManager: options.packageManager,
-        rootDirectory: options.root,
+        rootDirectory: options.root && getSystemPath(options.root),
       },
     );
     engineHost.registerTaskExecutor(
       BuiltinTaskExecutor.RepositoryInitializer,
       {
-        rootDirectory: options.root,
+        rootDirectory: options.root && getSystemPath(options.root),
       },
     );
     engineHost.registerTaskExecutor(BuiltinTaskExecutor.RunSchematic);