Add filter null check for ColumnIndex

This Jira is opened for discussion that should we add null checking for the filter when ColumnIndex is enabled.

In the ColumnIndexFilter#calculateRowRanges() method, the input parameter 'filter' is assumed to be non-null without checking. It throws NPE when ColumnIndex is enabled(by default) but there is no filter set in the ParquetReadOptions. The call stack is as below.
java.lang.NullPointerException
at org.apache.parquet.internal.filter2.columnindex.ColumnIndexFilter.calculateRowRanges(ColumnIndexFilter.java:81)
at org.apache.parquet.hadoop.ParquetFileReader.getRowRanges(ParquetFileReader.java:961)
at org.apache.parquet.hadoop.ParquetFileReader.readNextFilteredRowGroup(ParquetFileReader.java:891)

If we don't add, the user might need to choose to call readNextRowGroup() or readFilteredNextRowGroup() accordingly based on filter existence.

Thoughts?

**Reporter**: [Xinli Shang](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=shangx@uber.com) / @shangxinli
**Assignee**: [Xinli Shang](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=shangx@uber.com) / @shangxinli

_{**Note**: *This issue was originally created as [PARQUET-1901](https://issues.apache.org/jira/browse/PARQUET-1901). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Start with org.apache.parquet.internal.filter2.columnindex.ColumnIndexFilter.calculateRowRanges() at ColumnIndexFilter.java:81, then trace the calls from ParquetFileReader.getRowRanges() and readNextFilteredRowGroup(). Reproduce the no-filter case with ColumnIndex enabled and verify that handling a missing filter no longer raises the reported NullPointerException.

Written by the indexing model from the issue text.