Added HANDLER support for MEMORY tables

Added key and file version numbers to MEMORY tables so that we can detect if someone has changed them between HANDLER calls.


mysql-test/suite/handler/aria.result:
  Fixed result after test changes
mysql-test/suite/handler/handler.inc:
  Changed test to use combined key to ensure rows are returned in a pre-determinated order.
mysql-test/suite/handler/heap.result:
  New result
mysql-test/suite/handler/heap.test:
  Added test for HANDLER + HEAP
mysql-test/suite/handler/innodb.result:
  Fixed result after test changes
mysql-test/suite/handler/myisam.result:
  Fixed result after test changes
sql/sql_handler.cc:
  Fixed wrong parameter to ha_index_next_same()
storage/heap/ha_heap.cc:
  Abort key scan if table has changed.
  Abort table scan if table has been recreated.
storage/heap/ha_heap.h:
  Added support for HANDLER
storage/heap/hp_clear.c:
  Increase version number so that we can notice changes if using HANDLER
storage/heap/hp_delete.c:
  Increase key data version number on key changes.
storage/heap/hp_rfirst.c:
  Remember version of key data
  Give error if using read-first on hash key.
storage/heap/hp_rkey.c:
  Remember version of key data
storage/heap/hp_rlast.c:
  Remember version of key data
  Give error if using read-last on hash key.
storage/heap/hp_rnext.c:
  Fixed that we get next key from last search.
storage/heap/hp_rprev.c:
  Fixed that we get previous key from last search.
storage/heap/hp_scan.c:
  Remember version of key and file data
storage/heap/hp_update.c:
  Increase key data version number on key changes.
storage/heap/hp_write.c:
  Increase key data version number on key changes.

include/heap.h

@@ -136,6 +136,8 @@ typedef struct st_heap_share
   ulong min_records,max_records;	/* Params to open */
   ulonglong data_length,index_length,max_table_size;
   uint key_stat_version;                /* version to indicate insert/delete */
+  uint key_version;                     /* Updated on key change */
+  uint file_version;                    /* Update on clear */
   uint records;				/* records */
   uint blength;				/* records rounded up to 2^n */
   uint deleted;				/* Deleted records in database */
@@ -173,6 +175,8 @@ typedef struct st_heap_info
   enum ha_rkey_function last_find_flag;
   TREE_ELEMENT *parents[MAX_TREE_HEIGHT+1];
   TREE_ELEMENT **last_pos;
+  uint key_version;                     /* Version at last read */
+  uint file_version;                    /* Version at scan */
   uint lastkey_len;
   my_bool implicit_emptied;
 #ifdef THREAD