[scudo] Store more blocks in each TransferBatch (#70390)

Instead of always storing the same number of blocks as cached, we prefer
increasing the utilization by saving more blocks in a single
TransferBatch. This may slightly impact the performance, but it will
save a lot of memory used by BatchClassId (especially for larger
blocks).

GitOrigin-RevId: 1865c7ea8561407626fe5489ae07647035413d7c
4 files changed