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.*}

Beginne mit org.apache.parquet.internal.filter2.columnindex.ColumnIndexFilter.calculateRowRanges() bei ColumnIndexFilter.java:81 und verfolge anschließend die Aufrufe von ParquetFileReader.getRowRanges() und readNextFilteredRowGroup(). Reproduziere den Fall ohne Filter bei aktiviertem ColumnIndex und verifiziere, dass die Behandlung eines fehlenden Filters nicht mehr die gemeldete NullPointerException auslöst.

Vom Indexierungsmodell aus dem Issue-Text verfasst.