MDEV-31254 InnoDB: Trying to read doublewrite buffer page

buf_read_page_low(): Remove an error message and a debug assertion
that can be triggered when using innodb_page_size=4k and
innodb_file_per_table=0. In that case, buf_read_ahead_linear()
may be invoked on page 255, which is one less than the first
page of the doublewrite buffer (256).

storage/innobase/buf/buf0rea.cc

@@ -280,9 +280,7 @@ buf_read_page_low(
 	*err = DB_SUCCESS;
 
 	if (buf_dblwr.is_inside(page_id)) {
-		ib::error() << "Trying to read doublewrite buffer page "
-			<< page_id;
-		ut_ad(0);
+		*err = DB_CORRUPTION;
 nothing_read:
 		space->release();
 		return false;