Issue #3053656 by Sam152, JeroenT, Lendude, mglaman: Rename...

Issue #3053656 by Sam152, JeroenT, Lendude, mglaman: Rename action.post_udate.php to action.post_update.php

(cherry picked from commit 868feb2b)

core/modules/system/tests/src/Functional/Update/MoveActionsToCoreTest.php

@@ -18,7 +18,7 @@ class MoveActionsToCoreTest extends UpdatePathTestBase {
    */
   protected function setDatabaseDumpFiles() {
     $this->databaseDumpFiles = [
-      __DIR__ . '/../../../../tests/fixtures/update/drupal-8.bare.standard.php.gz',
+      __DIR__ . '/../../../../tests/fixtures/update/drupal-8.4.0.bare.standard.php.gz',
       __DIR__ . '/../../../../tests/fixtures/update/drupal-8.actions-2815379.php',
     ];
   }