In row_undo_ins_remove_clust_rec() and similar places,
an assertion !node->trx->dict_operation_lock_mode could fail,
because an online ALTER is not allowed to run at the same time
while DDL operations on the table are being rolled back.

This race condition would be fixed by always acquiring an InnoDB
table lock in ha_innobase::prepare_inplace_alter_table() or
prepare_inplace_alter_table_dict(), or by ensuring that recovered
transactions are protected by MDL that would block concurrent DDL
until the rollback has been completed.

This reverts commit 15093639
and commit 22c4a751.