Incorrect generation name in the heap verification log message with Serial GC

The log message when verifying young gen prints the name of the old generation:

void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
  log_debug(gc, verify)("%s", _old_gen->name());
  _old_gen->verify();

  log_debug(gc, verify)("%s", _old_gen->name());
  _young_gen->verify();

  log_debug(gc, verify)("RemSet");
  rem_set()->verify();
}