Add tests for single argument versions of infix:<==> and infix:<!=>.
Add tests for single argument versions of infix:<==> and infix:<!=>.

Someone with more time could go through and repeat this process for the other operators tested in this file...

cygx/roast,bitrauser/roast,dankogai/roast,dankogai/roast,b2gills/roast,b2gills/roast,dogbert17/roast,dankogai/roast,bitrauser/roast,laben/roast,perl6/roast,cygx/roast,niner/roast,niner/roast,skids/roast,zostay/roast,b2gills/roast,dogbert17/roast,skids/roast,skids/roast,zostay/roast,zostay/roast,laben/roast,niner/roast,laben/roast,cygx/roast