Trim down ExpandableMarshalledValueByteStream to the actual data length before storing in cache

When storeAsBinary configuration flag is used, the ExpandableMarshalledValueByteStream is used to serialize objects to byte arrays.
However, for value size up to 4kB, almost half of the space for each cache entry can be wasted because the ByteStream is stored as is - with the additional space for future expansion.
For value size greater than 4kB, only additional 25% of actual value size can be wasted. But as these values can be quite large, the wasted space gets bigger too.
It is not necessary to store ExpandableMarshalledValueByteStream as is and can be shrinked to actual data size before storing in cache.