Fix abusive usage of assert in ArrayUtil [LUCENE-8969]

Methods in `o.a.l.util.ArrayUtil` uses `assert` statements for argument checks.
It would be suitable to throw \`IllegalArgumentExceptions`s instead of assertions here, to improve traceability when the violations occur? Sometimes I had difficulty in identifying the cause of assertion errors...

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Migrated from [LUCENE-8969](https://issues.apache.org/jira/browse/LUCENE-8969) by Tomoko Uchida (@mocobeta)

Locate o.a.l.util.ArrayUtil and review the methods that use assert statements for argument checks. Replace those checks with IllegalArgumentExceptions, then verify that invalid arguments consistently produce the intended exceptions and that the relevant tests pass.

Written by the indexing model from the issue text.