Issue #3230507: Create build tests for case where site is using core recommended Composer project

tests/modules/automatic_updates_test/src/TestUpdater.php

@@ -34,7 +34,7 @@ class TestUpdater extends Updater {
    * {@inheritdoc}
    */
   public function getStageDirectory(): string {
-    return $this->stageDirectory ?: uniqid(parent::getStageDirectory());
+    return $this->stageDirectory ?: parent::getStageDirectory();
   }
 
 }