CrunchRecordReader creates new TaskAttemptContextImpl with DummyReporter

CrunchRecordReader creates a new TaskAttemptContextImpl to pass to the actual RecordReader.

The constructor used, defaults to a DummyReporter.

The effect of this is that counters & progress messages from the RecordReader are lost.

This could easily be fixed by creating a WrappedStatusReporter that delegates counter & progress calls to the original context.