Convert FullTextIndexServer writeRow() to use Row (not RowData) version
Find there is a ValuesRow and a ValuesHolderRow. Merge the former into
the latter and update everywhere not to use the ValueRow. This
consolidates all the list of objects into Row code in one place and
provides consistent interface for generated row access.
Update AbstractStoreIndexStatistics to use writeRow(row), not rowData.
Update the ExternalDataService to use store.WriteRow(Row). This requires
updating the RowReader to produce Rows, not rowDatas. Update tests to
reflect the use of Row, not RowData.