Add tests for size() and isEmpty() to checkSet() and checkMap().
Add tests for size() and isEmpty() to checkSet() and checkMap().

permazen/permazen,archiecobbs/jsimpledb,tempbottle/jsimpledb,archiecobbs/jsimpledb,gmsconstantino/jsimpledb,permazen/permazen,gmsconstantino/jsimpledb,archiecobbs/jsimpledb,mmayorivera/jsimpledb,tempbottle/jsimpledb,gmsconstantino/jsimpledb,permazen/permazen,mmayorivera/jsimpledb,mmayorivera/jsimpledb,tempbottle/jsimpledb