Draft: [#620] New v70005/name_level_order-gtmde327593 test for verify fixing of name-level $ORDER(gvn,-1)

Release note (http://tinco.pair.com/bhaskar/gtm/doc/articles/GTM_V7.0-005_Release_Notes.html#GTM-DE327593) says:

GT.M handles name-level $ORDER(gvn,-1)/$ZPREVIOUS(gvn) correctly when searching across subscript-level mappings in the global directory. In V7.0-004, $ORDER(gvn,-1), where gvn is an unsubscripted global, could return the same gvn instead of a previous global name or the null string. The workaround was to add global data to otherwise empty global maps between the specified gvn and its previous gvn, and optionally KILLing it afterwards, which leaves around sufficient residual information in the database to avoid the issue. (GTM-DE327593)