[SPARK-14116][SQL] Implements buildReader() for ORC data source

## What changes were proposed in this pull request?

This PR implements `FileFormat.buildReader()` for our ORC data source. It also fixed several minor styling issues related to `HadoopFsRelation` planning code path.

Note that `OrcNewInputFormat` doesn't rely on `OrcNewSplit` for creating `OrcRecordReader`s, plain `FileSplit` is just fine. That's why we can simply create the record reader with the help of `OrcNewInputFormat` and `FileSplit`.

## How was this patch tested?

Existing test cases should do the work

Author: Cheng Lian <lian@databricks.com>

Closes #11936 from liancheng/spark-14116-build-reader-for-orc.