Add a test for scripting on Windows (#3858)

* Add a test for scripting on Windows

.github/workflows/windows.yml

@@ -26,4 +26,7 @@ jobs:
     - name: Run Edge test
       run: node bin/sitespeed.js -b edge https://www.sitespeed.io/
       shell: cmd
-      
+    - name: Run Edge test with scripting
+      run: node bin/sitespeed.js -b edge --multi test/prepostscripts/multiWindows.cjs -n 1
+      shell: cmd
+    

test/prepostscripts/multiWindows.cjs

@@ -0,0 +1,3 @@
+module.exports = async function (context, commands) {
+    return commands.measure.start('https://www.sitespeed.io/');
+};