MDEV-19175 Server crashes in ha_partition::vers_can_native upon INSERT DELAYED into versioned partitioned table

Uninitialized LEX::part_info on ha_partition::vers_can_native().

mysql-test/suite/versioning/r/partition.result

@@ -549,6 +549,11 @@ t1	CREATE TABLE `t1` (
  PARTITION BY SYSTEM_TIME INTERVAL 7 SECOND
 (PARTITION `ver_p1` HISTORY ENGINE = DEFAULT_ENGINE,
  PARTITION `ver_pn` CURRENT ENGINE = DEFAULT_ENGINE)
+#
+# MDEV-19175 Server crashes in ha_partition::vers_can_native upon INSERT DELAYED into versioned partitioned table
+#
+create or replace table t1 (f int) with system versioning partition by hash(f);
+insert delayed into t1 values (1);
 # Test cleanup
 drop database test;
 create database test;

mysql-test/suite/versioning/t/partition.test

@@ -480,6 +480,14 @@ partition by system_time interval column_get(column_create(7,7), 7 as int) secon
 --replace_result $default_engine DEFAULT_ENGINE
 show create table t1;
 
+--echo #
+--echo # MDEV-19175 Server crashes in ha_partition::vers_can_native upon INSERT DELAYED into versioned partitioned table
+--echo #
+create or replace table t1 (f int) with system versioning partition by hash(f);
+# delayed works differently in embedded server
+--error 0,ER_DELAYED_NOT_SUPPORTED
+insert delayed into t1 values (1);
+
 --echo # Test cleanup
 drop database test;
 create database test;

sql/sql_lex.cc

@@ -3225,7 +3225,7 @@ void Query_tables_list::destroy_query_tables_list()
 */
 
 LEX::LEX()
-  : explain(NULL), result(0), arena_for_set_stmt(0), mem_root_for_set_stmt(0),
+  : explain(NULL), result(0), part_info(NULL), arena_for_set_stmt(0), mem_root_for_set_stmt(0),
     option_type(OPT_DEFAULT), context_analysis_only(0), sphead(0),
     default_used(0), is_lex_started(0), limit_rows_examined_cnt(ULONGLONG_MAX)
 {