Port of commit ba731bdc6a80e88d32e7440044b548c3e3edc591

from server/columnstore_cache

Commit message:

Fixed crashed bug on simple insert

Other things:
- Added test from columnstore team
- Fixed two reported bugs from columnstore team
- Call free_locks as part of start_trans() instead of get_status()
  to ensure that we have locks both for cached table and cache table
  before we try to free any.
- Store pointers to lock->get_status and lock->update_status for the
  cached table. Was needed by ha_tina in flush_insert_cache to make
  new insert rows visible for the SELECT that caused the flush

dbcon/mysql/ha_mcs.h

@@ -304,6 +304,7 @@ public:
   int flush_insert_cache();
   friend my_bool get_status_and_flush_cache(void *param,
                                             my_bool concurrent_insert);
+  friend my_bool cache_start_trans(void *param);
 };
 
 #endif //HA_MCS_H__