fix additional edge cases in stacked code
fix additional edge cases in stacked code

single stack mode erroneously triggered with areaMode=stacked
more drawAsInfinite edge cases

Krylon360/evernote-graphite-web,Krylon360/evernote-graphite-web,Krylon360/evernote-graphite-web,Krylon360/evernote-graphite-web,evernote/graphite-web,Talkdesk/graphite-web,Talkdesk/graphite-web,Talkdesk/graphite-web,Krylon360/evernote-graphite-web,evernote/graphite-web,Talkdesk/graphite-web,evernote/graphite-web,Talkdesk/graphite-web,Krylon360/evernote-graphite-web,evernote/graphite-web,evernote/graphite-web,Talkdesk/graphite-web