Delta Encoding is not used when dictionary enabled

Current code doesn't enable using both Delta Encoding and Dictionary Encoding. If I instantiate ParquetWriter like this :
```Java
val writer = new ParquetWriter[Group](outFile, new GroupWriteSupport, codec, blockSize, pageSize, dictPageSize, enableDictionary = true, true, ParquetProperties.WriterVersion.PARQUET_2_0, configuration)
```

Then this piece of code :
https://github.com/apache/parquet-mr/blob/master/parquet-column/src/main/java/org/apache/parquet/column/values/factory/DefaultValuesWriterFactory.java#L78-L86

Causes that DictionaryValuesWriter is used instead of the inferred DeltaLongEncodingWriter.

The original issue is here : https://github.com/apache/parquet-mr/pull/154#issuecomment-266489768

**Reporter**: [Jakub Liska](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=l154k)

_{**Note**: *This issue was originally created as [PARQUET-796](https://issues.apache.org/jira/browse/PARQUET-796). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

parquet-column/src/main/java/org/apache/parquet/column/values/factory/DefaultValuesWriterFactory.java の78-86行目から始め、推論された DeltaLongEncodingWriter ではなく DictionaryValuesWriter が選択される経緯を追ってください。Issue の ParquetWriter 設定を再現し、dictionary encoding が有効な場合に期待される encoding の動作を示すテストカバレッジを追加してください。

索引モデルが issue の本文から書いたものです。