MDEV-29435 CHECK TABLE forgets to release latches after reporting failure

btr_validate_level(): Invoke mtr.commit() after a failure.
This omission was introduced in
commit 0b47c126 (MDEV-13542).

mysql-test/suite/innodb/r/leaf_page_corrupted_during_recovery.result

@@ -17,4 +17,8 @@ pk	c
 1	sql
 SELECT * FROM t1 WHERE pk = 12;
 ERROR HY000: Index for table 't1' is corrupt; try to repair it
+CHECK TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	Warning	InnoDB: The B-tree of index PRIMARY is corrupted.
+test.t1	check	error	Corrupt
 DROP TABLE t1;

mysql-test/suite/innodb/t/leaf_page_corrupted_during_recovery.test

@@ -11,6 +11,7 @@ call mtr.add_suppression("\\[ERROR\\] InnoDB: We detected index corruption");
 call mtr.add_suppression("\\[ERROR\\] (mysqld|mariadbd).*: Index for table 't1' is corrupt; try to repair it");
 call mtr.add_suppression("InnoDB: btr_pcur_open_low level: 0 table: `test`\\.`t1` index: `PRIMARY`");
 call mtr.add_suppression("InnoDB: File '.*test/t1\\.ibd' is corrupted");
+call mtr.add_suppression("InnoDB: In page .* of index `PRIMARY` of table `test`\\.`t1`");
 --enable_query_log
 CREATE TABLE t1 (pk INT PRIMARY KEY, c CHAR(255))ENGINE=InnoDB STATS_PERSISTENT=0;
 
@@ -54,6 +55,7 @@ let $restart_parameters=--innodb-force-recovery=2;
 SELECT * FROM t1 WHERE PK = 1;
 --error ER_NOT_KEYFILE
 SELECT * FROM t1 WHERE pk = 12;
+CHECK TABLE t1;
 
 DROP TABLE t1;
 let $restart_parameters=;

storage/innobase/btr/btr0btr.cc

@@ -4879,6 +4879,7 @@ btr_validate_level(
 loop:
 	if (!block) {
 invalid_page:
+		mtr.commit();
 func_exit:
 		mem_heap_free(heap);
 		return err;