Changes to work with older versions of GT.M

Older (pre-YottaDB) versions of GT.M prior to V6.2-002 did not have $zut, and also reported fewer statistics using $view("gvstat",…) than current versions. The changes use $horolog for timing if $zut is not available. Also, since ^gvstat and ^gvstatinc may include statistics from multiple versions of YottaDB/GT.M, and since statistics from a newer version may be a superset of statistics from an older version, track the statistics names separately in ^gvstatname and so that the CSV output fields like up correctly even when statistics from multiple versions is output.