[Improment]Add workload condition query used memory

[wangbo]

Proposed changes

Add workload condition query used memory, we can kill queries based on memory usage.

1 create a policy which can kill query used memory exceeds 100M.

create workload policy memory_used_policy conditions(query_be_memory_bytes > 104857600) actions(cancel_query);

2 submit a query.

mysql [hits]>insert into hits2 select * from hits;
ERROR 1105 (HY000): errCode = 2, detailMessage = (10.16.10.8)[INTERNAL_ERROR]query 81c39e2b3ecf461c-bc78ad6d9b6173d2 cancelled by workload policy memory_used_policy, id:29028