seekToRow in RecordReaderImpl does not update rowInStripe which can caus...

...e readers to read off the end of streams because a new stripe may not be read when the end of the stripe is reached.

Added a test case to demonstrate this.

Also, modified another test case to call seekToRow to skip <n> rows instead of calling seekToRow for each row regardless of whether the row is read or not.

Tests pass.