[sas mode] Fix tokenizing of empty strings
[sas mode] Fix tokenizing of empty strings

Closes #4178

rrandom/CodeMirror,adobe/CodeMirror2,codio/CodeMirror,codio/CodeMirror,nightwing/CodeMirror,sourcelair/CodeMirror,kerabromsmu/CodeMirror,ejgallego/CodeMirror,pabloferz/CodeMirror,kerabromsmu/CodeMirror,ejgallego/CodeMirror,rrandom/CodeMirror,xeronith/CodeMirror,schanzer/CodeMirror,alur/CodeMirror,jkaplon/CodeMirror,kerabromsmu/CodeMirror,jkaplon/CodeMirror,schanzer/CodeMirror,crazy4chrissi/CodeMirror,TDaglis/CodeMirror,pabloferz/CodeMirror,dperetti/CodeMirror,thomasjm/CodeMirror,thomasjm/CodeMirror,INTELOGIE/CodeMirror,xeronith/CodeMirror,sourcelair/CodeMirror,alur/CodeMirror,INTELOGIE/CodeMirror,schanzer/CodeMirror,notepadqq/CodeMirror,ficristo/CodeMirror,grzegorzmazur/CodeMirror,MarcelGerber/CodeMirror,rrandom/CodeMirror,hackmdio/CodeMirror,mtaran-google/CodeMirror,notepadqq/CodeMirror,dperetti/CodeMirror,crazy4chrissi/CodeMirror,jayaprabhakar/CodeMirror,dperetti/CodeMirror,grzegorzmazur/CodeMirror,adobe/CodeMirror2,nightwing/CodeMirror,pabloferz/CodeMirror,namin/CodeMirror,notepadqq/CodeMirror,jayaprabhakar/CodeMirror,SidPresse/CodeMirror,mtaran-google/CodeMirror,wingify/CodeMirror,ejgallego/CodeMirror,INTELOGIE/CodeMirror,xeronith/CodeMirror,ficristo/CodeMirror,thomasjm/CodeMirror,namin/CodeMirror,jkaplon/CodeMirror,hackmdio/CodeMirror,adobe/CodeMirror2,crazy4chrissi/CodeMirror,hackmdio/CodeMirror,wingify/CodeMirror,SidPresse/CodeMirror,ficristo/CodeMirror,MarcelGerber/CodeMirror,codio/CodeMirror,MarcelGerber/CodeMirror,SidPresse/CodeMirror,TDaglis/CodeMirror,jayaprabhakar/CodeMirror,sourcelair/CodeMirror,wingify/CodeMirror,namin/CodeMirror,grzegorzmazur/CodeMirror,alur/CodeMirror,mtaran-google/CodeMirror,TDaglis/CodeMirror,nightwing/CodeMirror