MDEV-13536 DB_TRX_ID is not actually being reset when the history is removed

This should have been part of MDEV-12288.

trx_undo_t::del_marks: Remove.
Purge needs to process all undo log records in order to
reset the DB_TRX_ID. Before MDEV-12288, it sufficed to only delete
the purgeable delete-marked records, and it ignore other undo log.

trx_rseg_t::needs_purge: Renamed from trx_rseg_t::last_del_marks.
Indicates whether a rollback segment needs to be processed by purge.

TRX_UNDO_NEEDS_PURGE: Renamed from TRX_UNDO_DEL_MARKS.
Indicates whether a rollback segment needs to be processed by purge.
This will be 1 until trx_purge_free_segment() has been invoked.

row_purge_record_func(): Set the is_insert flag for TRX_UNDO_INSERT_REC,
so that the DB_ROLL_PTR will match in row_purge_reset_trx_id().

trx_purge_fetch_next_rec(): Add a comment about row_purge_record_func()
going to set the is_insert flag.

trx_purge_read_undo_rec(): Always attempt to read the undo log record.

trx_purge_get_next_rec(): Do not skip any undo log records.
Even when no clustered index record is going to be removed,
we may want to reset some DB_TRX_ID,DB_ROLL_PTR.

trx_undo_rec_get_cmpl_info(), trx_undo_rec_get_extern_storage(): Remove.

trx_purge_add_undo_to_history(): Set the TRX_UNDO_NEEDS_PURGE flag
so that the resetting will work on undo logs that were originally
created before MDEV-12288 (MariaDB 10.3.1).

trx_undo_roll_ptr_is_insert(), trx_purge_free_segment(): Cleanup
(should be no functional change).

mysql-test/suite/innodb_zip/r/cmp_per_index.result

@@ -1,3 +1,5 @@
+SET GLOBAL innodb_purge_rseg_truncate_frequency=1;
+SET GLOBAL innodb_fast_shutdown=0;
 SET GLOBAL innodb_cmp_per_index_enabled=ON;
 SELECT * FROM information_schema.innodb_cmp_per_index;
 CREATE TABLE t (