Min() and Max() on Timestamp and Date columns for ORC returns wrong results

min() and max() of timestamp and date columns of ORC table returns wrong results. The reason for that is when ORC creates object inspectors for date and timestamp it uses JAVA primitive objects as opposed to WRITABLE objects. When get() is performed on java primitive objects, a reference to the underlying object is returned whereas when get() is performed on writable objects, a copy of the underlying object is returned.

Fix is to change the object inspector creation to return writable objects for timestamp and date.