MultiCollector to control skipping docs on field sort [LUCENE-10224]

Currently MultiCollector::MultiLeafCollector doesn't implement competitiveIterator; so it doesn't have an ability to skip non-competitive documents on field sort. Check when it is useful to have this ability : 1) e.g. when MultiCollector contains only a single sub-collector 2) when multiple sub-collectors have the same sort fields

Another thing we need to do is to disable skipping functionality of all sub-collectors if the combined scoreMode of MultiCollectors is scoreMode.isExhaustive() == true. Because currently is one of sub-collectors is TopFieldCollector and its scoreMode is not exhaustive, it will update its competitiveIterator when its hits threshold is reached, even though we will never end up using this competitiveIterator, so useless work is done here.

Relates to #10320

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Migrated from [LUCENE-10224](https://issues.apache.org/jira/browse/LUCENE-10224) by Mayya Sharipova (@mayya-sharipova)

Start at MultiCollector::MultiLeafCollector and trace how sub-collectors expose competitiveIterator and combined scoreMode. Check the single-sub-collector and same-sort-field cases, including when the combined score mode is exhaustive. Done means the requested skipping behavior is covered by tests for these cases.

Written by the indexing model from the issue text.