Issue #2194357 by alexpott, Berdir: CacheArray::__destruct() invoked after...

Issue #2194357 by alexpott, Berdir: CacheArray::__destruct() invoked after test tables have been removed.

core/modules/simpletest/lib/Drupal/simpletest/TestBase.php

@@ -1148,6 +1148,10 @@ private function restoreEnvironment() {
       }
     }
 
+    // Sleep for 50ms to allow shutdown functions and terminate events to
+    // complete. Further information: https://drupal.org/node/2194357.
+    usleep(50000);
+
     // Remove all prefixed tables.
     // @todo Connection prefix info is not normalized into an array.
     $original_connection_info = Database::getConnectionInfo('simpletest_original_default');