Add test for explicit 1x source after test for implied 1x source (1x omitted).
Add test for explicit 1x source after test for implied 1x source (1x omitted).

patrickkettner/picturefill,iancrowther/picturefill,footiealf/picturefill,chrismcandrew/picturefill,footiealf/picturefill,yubin-huang/picturefill,scottjehl/picturefill,scottjehl/picturefill,rockmandew/picturefill,albell/picturefill,demateu/picturefill,nucliweb/picturefill,purposeindustries/picturefill,guardian/picturefill,samiadelgado/picturefill,guardian/picturefill,rockmandew/picturefill,iancrowther/picturefill,yufi113/picturefill,mcanthony/picturefill,yufi113/picturefill,ddeveloperr/picturefill,mcanthony/picturefill,demateu/picturefill,samiadelgado/picturefill,purposeindustries/picturefill,chrismcandrew/picturefill,ddeveloperr/picturefill,albell/picturefill,yubin-huang/picturefill,patrickkettner/picturefill