MDEV-23332 Index online status assert failure in btr_search_drop_page_hash_index

Problem:
========
In row_merge_drop_indexes(), InnoDB drops only the index from
dictionary and frees the index pages but it maintains the index
object if the table is being used by other DML threads. It sets
the online status of the index to ONLINE_INDEX_ABORTED_DROPPED.
Removing the index from dictionary doesn't remove the
corressponding ahi entries of the index. When block is being
reused, InnoDB tries to remove ahi entries for the block and
it fails if index online status is ONLINE_INDEX_ABORTED_DROPPED.

Fix:
====
MDEV-22456 allows the index ahi entries to be dropped lazily.
so checking online status in btr_search_drop_page_hash_index()
is meaningless and should be removed.

storage/innobase/btr/btr0sea.cc

@@ -1160,26 +1160,6 @@ btr_search_drop_page_hash_index(buf_block_t* block)
 	      || block->page.id.space() == index->space);
 	ut_a(index_id == index->id);
 	ut_ad(!dict_index_is_ibuf(index));
-#ifdef UNIV_DEBUG
-	switch (dict_index_get_online_status(index)) {
-	case ONLINE_INDEX_CREATION:
-		/* The index is being created (bulk loaded). */
-	case ONLINE_INDEX_COMPLETE:
-		/* The index has been published. */
-	case ONLINE_INDEX_ABORTED:
-		/* Either the index creation was aborted due to an
-		error observed by InnoDB (in which case there should
-		not be any adaptive hash index entries), or it was
-		completed and then flagged aborted in
-		rollback_inplace_alter_table(). */
-		break;
-	case ONLINE_INDEX_ABORTED_DROPPED:
-		/* The index should have been dropped from the tablespace
-		already, and the adaptive hash index entries should have
-		been dropped as well. */
-		ut_error;
-	}
-#endif /* UNIV_DEBUG */
 
 	n_fields = block->curr_n_fields;
 	n_bytes = block->curr_n_bytes;