Do we suboptimally call ByteBuffersDataOutput.toDataInput()?

### Description

See this comment: https://github.com/apache/lucene/pull/12624#issuecomment-1829633268

> I wonder: are there other places in Lucene that might fall prey to this performance trap (calling toDataInput frequently while continuing to append bytes to the DataOutput)? FreqProxTermsWriter seems to use this for each term to re-read the postings (maybe for the static sort use case).

Start with the comment on pull request 12624, then inspect FreqProxTermsWriter and its use of ByteBuffersDataOutput.toDataInput() for each term. Check whether input recreation occurs while bytes are still being appended; done means identifying any confirmed performance trap and the affected call sites.

Written by the indexing model from the issue text.