MDEV-22608 ASAN use-after-poison in TABLE::check_period_overlaps

The bug was fixed by MDEV-22599 bugfix, which changed `Field::cmp` call
to `Field::cmp_prefix` in `TABLE::check_period_overlaps`.

The trick is that `Field_bit::cmp` apparently calls `Field_bit::cmp_key`,
which condiders an argument an actual pointer to data, which isn't correct
for `Field_bit`, since it stores data by `bit_ptr`. which is in the
beginning of the record, and using `ptr` is incorrect (we use it through
`ptr_in_record` call)

mysql-test/suite/period/r/overlaps.result

@@ -337,4 +337,11 @@ insert into t values (1,'1988-08-25','2024-03-06');
 create or replace table t1 (a int) engine=myisam;
 insert into t1 values (1),(2);
 update t join t1 set s = '2020-01-01';
+# MDEV-22608 ASAN use-after-poison in TABLE::check_period_overlaps
+create or replace table t1 (s date, e date, b bit, period for p(s,e),
+unique(b, p without overlaps)) engine=myisam;
+insert into t1 values ('2024-12-21','2034-06-29',0),
+('2024-12-21','2034-06-29',1);
+update t1 set b = 1;
+ERROR 23000: Duplicate entry '\x01-2034-06-29-2024-12-21' for key 'b'
 drop table t, t1;

mysql-test/suite/period/t/overlaps.test

@@ -324,4 +324,15 @@ insert into t1 values (1),(2);
 
 update t join t1 set s = '2020-01-01';
 
+
+--echo # MDEV-22608 ASAN use-after-poison in TABLE::check_period_overlaps
+
+create or replace table t1 (s date, e date, b bit, period for p(s,e),
+                            unique(b, p without overlaps)) engine=myisam;
+insert into t1 values ('2024-12-21','2034-06-29',0),
+                      ('2024-12-21','2034-06-29',1);
+--error ER_DUP_ENTRY
+update t1 set b = 1;
+
+
 drop table t, t1;