MDEV-25950 Ignoring strange row from mysql.innodb_index_stats after DDL

commit_try_rebuild(): Invoke trx_t::drop_table_statistics()
with the correct (original) name of the table.
This fixes a regression that was introduced in
commit 1bd681c8 (MDEV-25506 part 3).

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

@@ -232,5 +232,17 @@ t1	ind3	n_diff_pfx01
 t1	ind3	n_diff_pfx02
 t1	ind3	n_leaf_pages
 t1	ind3	size
+ALTER TABLE t1 DROP b, FORCE;
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
+table_name	index_name	stat_name
+t1	GEN_CLUST_INDEX	n_diff_pfx01
+t1	GEN_CLUST_INDEX	n_leaf_pages
+t1	GEN_CLUST_INDEX	size
+t1	ind2	n_diff_pfx01
+t1	ind2	n_diff_pfx02
+t1	ind2	n_leaf_pages
+t1	ind2	size
 UPDATE t1 SET a = 1 WHERE c = 'foo';
 DROP TABLE t1;
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
+table_name	index_name	stat_name

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

@@ -225,5 +225,9 @@ ALTER TABLE t1 DROP INDEX ind2, ADD INDEX ind3(b),
 
 SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
 
+ALTER TABLE t1 DROP b, FORCE;
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;
+
 UPDATE t1 SET a = 1 WHERE c = 'foo';
 DROP TABLE t1;
+SELECT table_name, index_name, stat_name FROM mysql.innodb_index_stats;

storage/innobase/handler/handler0alter.cc

@@ -9961,10 +9961,11 @@ commit_try_rebuild(
 		error = row_rename_table_for_mysql(
 			rebuilt_table->name.m_name, old_name, trx, false);
 		if (error == DB_SUCCESS) {
-			error = trx->drop_table_statistics(
-				ctx->old_table->name);
+			/* The statistics for the surviving indexes will be
+			re-inserted in alter_stats_rebuild(). */
+			error = trx->drop_table_statistics(old_name);
 			if (error == DB_SUCCESS) {
-				error = trx->drop_table(*ctx->old_table);
+				error = trx->drop_table(*user_table);
 			}
 		}
 	}