[Subtask]: 对象分配优化：fifocache.shardCacheKey

[volgariver6]

Parent Issue

https://github.com/matrixorigin/MO-Cloud/issues/4871

Detail of Subtask

优化 fifocache.shardCacheKey() 中大量小对象分配导致的gc压力过大问题

http://47.96.110.240/explore?panes=%7B%22m0O%22:%7B%22datasource%22:%22ff8fe218-8a78-43f2-a5ef-3fee100657e2%22,%22queries%22:%5B%7B%22groupBy%22:%5B%5D,%22labelSelector%22:%22%7Bnamespace%3D%5C%22freetier-01%5C%22,%20pod%3D%5C%22freetier-01-s2-6475fc8dcb-cn-68grb%5C%22%7D%22,%22queryType%22:%22both%22,%22refId%22:%22A%22,%22profileTypeId%22:%22memory:alloc_objects:count:space:bytes%22,%22datasource%22:%7B%22type%22:%22grafana-pyroscope-datasource%22,%22uid%22:%22ff8fe218-8a78-43f2-a5ef-3fee100657e2%22%7D%7D%5D,%22range%22:%7B%22from%22:%221739268000000%22,%22to%22:%221739268555000%22%7D%7D%7D&schemaVersion=1&orgId=1

Describe implementation you've considered

No response

Additional information

No response