Add tests for StoredTabletFile range serialization/deserialization

This is a follow on to #3621. As pointed out here https://github.com/apache/accumulo/pull/3621#discussion_r1265688298 the current implementation of TabletFileCq object will always have a valid range when construction the object. We should add some tests to verify and make sure this doesn't change and then we can get rid of the runtime validation check for verifying a range is a row range.

Read issue #3621 and the linked pull-request discussion first, then inspect StoredTabletFile and TabletFileCq to understand their range serialization and deserialization. Add tests showing that construction preserves a valid row range and that serialization round-trips it correctly; the tests should guard the behavior described in this issue.

Written by the indexing model from the issue text.