AvroRecord refuses Union[null, RecordSchema]

Apache avro record constructor ensure that its parameter is a Record Schema, and so refuse Union[null, RecordSchema].

On TCK, when we build AvroRecord from Entry, we use the entry schema to build the record. As the entry can be nullable; the entry type is an union[null, Record].

Then, this code failed.

this.delegate = new GenericData.Record(this.schema.getActualDelegate());

to fix, we we to check the type of schema => actual delegate, and extract record schema in case of union.