LocalCache and PageStore should reuse the byte array buffer in the write path

[beinan]

Summary In the current local cache implementation, when we write the data sequentially, we always create a new byte array for each page, but in fact, for each file/stream to write, we can reuse the same bytes array to Reduce memory allocation and GC pressure.

https://github.com/swhzzh/alluxio-2.3.0-origin/blob/5fccbcbe6dd372173d478ff74303567de3894951/core/client/fs/src/main/java/alluxio/client/file/cache/LocalCacheFileInStream.java#L314

and https://github.com/Alluxio/alluxio/pull/15887#discussion_r925067026

Urgency Medium