MDEV-15951 system versioning by trx id doesn't work with partitioning

Fix partitioning for trx_id-versioned tables.
`partition by hash`, `range` and others now work.
`partition by system_time` is forbidden.
Currently we cannot use row_start and row_end in `partition by`, because
insertion of versioned field is done by engine's handler, as well as
row_start/row_end's value set up, which is a transaction id -- so it's
also forbidden.

The drawback is that it's now impossible to use `partition by key()`
without parameters for such tables, because it references row_start and
row_end implicitly.

* add handler::vers_can_native()
* drop Table_scope_and_contents_source_st::vers_native()
* drop partition_element::find_engine_flag as unused
* forbid versioning partitioning for trx_id as not supported
* adopt vers tests for trx_id partitioning
* forbid any row_end referencing in `partition by` clauses,
  including implicit `by key()`

1 files changed, 16 insertions, 0 deletions

diff --git a/sql/ha_partition.h b/sql/ha_partition.h
index 202f27840dc..e1f1503f8ec 100644
--- a/sql/ha_partition.h
+++ b/sql/ha_partition.h
@@ -412,6 +412,22 @@ public:
 
   virtual void return_record_by_parent();
 
+  virtual bool vers_can_native(THD *thd)
+  {
+    if (thd->lex->part_info)
+    {
+      // PARTITION BY SYSTEM_TIME is not supported for now
+      return thd->lex->part_info->part_type != VERSIONING_PARTITION;
+    }
+    else
+    {
+      bool can= true;
+      for (uint i= 0; i < m_tot_parts && can; i++)
+        can= can && m_file[i]->vers_can_native(thd);
+      return can;
+    }
+  }
+
   /*
     -------------------------------------------------------------------------
     MODULE create/delete handler object