BUG#11759349 - 51655: CREATE TABLE IN MEMORY ENGINE DOESN'T STORE

CREATE_TIME IN INFORMATION_SC

It was impossible to determine MEMORY table creation time,
since it wasn't stored/exposed.

With this patch creation time is saved and it is available via
I_S.TABLES.CREATE_TIME.

Note: it was decided that additional analysis is required before
implementing UPDATE_TIME. Thus this patch doesn't store UPDATE_TIME.

include/heap.h

@@ -50,6 +50,7 @@ typedef struct st_heapinfo		/* Struct from heap_info */
   uint reclength;			/* Length of one record */
   int errkey;
   ulonglong auto_increment;
+  time_t create_time;
 } HEAPINFO;
 
 
@@ -146,6 +147,7 @@ typedef struct st_heap_share
   uint open_count;
   uchar *del_link;			/* Link to next block with del. rec */
   char * name;			/* Name of "memory-file" */
+  time_t create_time;
 #ifdef THREAD
   THR_LOCK lock;
   pthread_mutex_t intern_lock;		/* Locking for use with _locking */