MDEV-18456 Assertion `item->maybe_null' failed in Type_handler_temporal_result::make_sort_key

Adding tests only.

This problem was earlier fixed in 10.4 by MDEV-17325 and backported to 10.3
with this commit:

  f4019f5b

mysql-test/main/func_hybrid_type.result

@@ -3915,5 +3915,20 @@ t1	CREATE TABLE `t1` (
 DROP TABLE t1;
 SET sql_mode=DEFAULT;
 #
+# MDEV-18456 Assertion `item->maybe_null' failed in Type_handler_temporal_result::make_sort_key
+#
+CREATE TABLE t1 (t TIME NOT NULL);
+INSERT INTO t1 VALUES ('00:20:11'),('14:52:05');
+SELECT GREATEST('9999', t) FROM t1 ORDER BY 1;
+GREATEST('9999', t)
+NULL
+NULL
+Warnings:
+Warning	1292	Truncated incorrect time value: '9999'
+Warning	1292	Truncated incorrect time value: '9999'
+Warning	1292	Truncated incorrect time value: '9999'
+Warning	1292	Truncated incorrect time value: '9999'
+DROP TABLE t1;
+#
 # End of 10.3 tests
 #

mysql-test/main/func_hybrid_type.test

@@ -710,6 +710,16 @@ SHOW CREATE TABLE t1;
 DROP TABLE t1;
 SET sql_mode=DEFAULT;
 
+--echo #
+--echo # MDEV-18456 Assertion `item->maybe_null' failed in Type_handler_temporal_result::make_sort_key
+--echo #
+
+CREATE TABLE t1 (t TIME NOT NULL);
+INSERT INTO t1 VALUES ('00:20:11'),('14:52:05');
+SELECT GREATEST('9999', t) FROM t1 ORDER BY 1;
+DROP TABLE t1;
+
+
 --echo #
 --echo # End of 10.3 tests
 --echo #