[Java] ListVector's setValueCount does not set inner vector's value count correctly

In ListVector#setValueCount, we always compute data vector's value count based on lastSet - this is incorrect when valueCount is less than lastSet

**Reporter**: [Prudhvi Porandla](https://issues.apache.org/jira/browse/ARROW-8842) / @pprudhvi
#### PRs and other links:
- [GitHub Pull Request apache/arrow#7214](https://github.com/apache/arrow/pull/7214)

_{**Note**: *This issue was originally created as [ARROW-8842](https://issues.apache.org/jira/browse/ARROW-8842). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start at ListVector#setValueCount in the Apache Arrow Java source and review the linked pull request apache/arrow#7214 for the intended behavior. Trace how the data vector's value count is computed when valueCount is less than lastSet, then run the relevant ListVector tests if available. Done means the inner vector receives the correct count in that case.

Written by the indexing model from the issue text.