drupal_get_bootstrap_phase / drupal_bootstrap is broken

It does return drupal_bootstrap(); but drupal_bootstrap($phase = NULL, $new_phase = TRUE) so this triggers a $new_phase causing if ($new_phase) { $final_phase = $phase; } to fire, breaking the bootstrap if it's not completed. Two fixes are necessary:

1. Do not allow drupal_bootstrap to store a phase it already passed.
2. Change the getter to return drupal_bootstrap(NULL, FALSE);