A cleanup for MDEV-10914 ROW data type for stored routine variables

Changing datatypes for:
- Item_spvar_args::m_table
- sp_rcontext::m_var_table
- return value of create_virtual_tmp_table()
from TABLE* to Virtual_tmp_table*

Advantages:
- Stricter data type control
- Removing the duplicate code (a loop with free_blobs)
  from destructors ~sp_rcontext() and ~Item_spvar_args(),
  using "delete m_(var_)table" in both instead.
- Using Virtual_tmp_table::delete makes the code call Field::delete,
  which calls TRASH() for the freed fields,
  which is good for valgrind test runs.

1 files changed, 2 insertions, 1 deletions

diff --git a/sql/sp_rcontext.h b/sql/sp_rcontext.h
index 93c8cacc70a..9a4a8e27032 100644
--- a/sql/sp_rcontext.h
+++ b/sql/sp_rcontext.h
@@ -34,6 +34,7 @@ class sp_instr_cpush;
 class Query_arena;
 class sp_head;
 class Item_cache;
+class Virtual_tmp_table;
 
 
 /*
@@ -365,7 +366,7 @@ private:
   const sp_pcontext *m_root_parsing_ctx;
 
   /// Virtual table for storing SP-variables.
-  TABLE *m_var_table;
+  Virtual_tmp_table *m_var_table;
 
   /// Collection of Item_field proxies, each of them points to the
   /// corresponding field in m_var_table.