MDEV-26041 Recovery failure due to delete-marked SYS_FIELDS record

trx_t::drop_table(): Delete-mark the SYS_TABLES and SYS_INDEXES
record before delete-marking any SYS_COLUMNS or SYS_FIELDS records.
Otherwise, dict_load_indexes() could fail on recovery. This fixes up
commit 1bd681c8 (MDEV-25506).

storage/innobase/dict/drop.cc

@@ -205,18 +205,19 @@ dberr_t trx_t::drop_table(const dict_table_t &table)
                       "WHERE TABLE_ID=:id FOR UPDATE;\n"
 
                       "BEGIN\n"
+
+                      "DELETE FROM SYS_TABLES WHERE ID=:id;\n"
+                      "DELETE FROM SYS_COLUMNS WHERE TABLE_ID=:id;\n"
+
                       "OPEN idx;\n"
                       "WHILE 1 = 1 LOOP\n"
                       "  FETCH idx INTO iid;\n"
                       "  IF (SQL % NOTFOUND) THEN EXIT; END IF;\n"
-                      "  DELETE FROM SYS_FIELDS WHERE INDEX_ID=iid;\n"
                       "  DELETE FROM SYS_INDEXES WHERE CURRENT OF idx;\n"
+                      "  DELETE FROM SYS_FIELDS WHERE INDEX_ID=iid;\n"
                       "END LOOP;\n"
                       "CLOSE idx;\n"
 
-                      "DELETE FROM SYS_COLUMNS WHERE TABLE_ID=:id;\n"
-                      "DELETE FROM SYS_TABLES WHERE ID=:id;\n"
-
                       "END;\n", FALSE, this);
 }