Bug #36705 key_buffer_size of >= 2G allocates all availabel virtual memory on 64-bit wondo.

temporary variables of 'long' types were used to store ulong values,
that causes init_key_cache to receive distorted parameters

sql/handler.cc

@@ -2350,8 +2350,8 @@ int ha_init_key_cache(const char *name, KEY_CACHE *key_cache)
   if (!key_cache->key_cache_inited)
   {
     pthread_mutex_lock(&LOCK_global_system_variables);
-    long tmp_buff_size= (long) key_cache->param_buff_size;
-    long tmp_block_size= (long) key_cache->param_block_size;
+    ulong tmp_buff_size= (ulong) key_cache->param_buff_size;
+    uint tmp_block_size= (uint) key_cache->param_block_size;
     uint division_limit= key_cache->param_division_limit;
     uint age_threshold=  key_cache->param_age_threshold;
     pthread_mutex_unlock(&LOCK_global_system_variables);