Fix guard condition for nested cofixpoints in checker.
Fix guard condition for nested cofixpoints in checker.

ejgallego/coq,silene/coq,letouzey/coq-wip,gares/coq,Zimmi48/coq,pirapira/coq2rust,maximedenes/coq,asr/coq,ale-f/coq,maximedenes/coq,barras/coq,asr/coq,TheTypoMaster/coq,gares/coq,SkySkimmer/coq,JasonGross/coq,JasonGross/coq,shindere/coq,Lionel-Rieg/coq,maximedenes/coq,letouzey/coq-wip,amintimany/coq,pirapira/coq2rust,ppedrot/coq,Matafou/coq,JasonGross/coq,gmalecha/coq,Lionel-Rieg/coq,william-lawvere/coq,ppedrot/coq,herbelin/github-coq,SkySkimmer/coq,8l/coq,SkySkimmer/coq,william-lawvere/coq,silene/coq,8l/coq,letouzey/coq-wip,silene/coq,mattam82/coq,maximedenes/coq,Lionel-Rieg/coq,jpdeplaix/coq,TheTypoMaster/coq,mattam82/coq,ppedrot/coq,gares/coq,ejgallego/coq,JasonGross/coq,gmalecha/coq,Ptival/coq,amintimany/coq,jpdeplaix/coq,ale-f/coq,mlasson/coq,asr/coq,TheTypoMaster/coq,aspiwack/coq,TOSPIO/coq,ale-f/coq,SkySkimmer/coq,Ptival/coq,mattam82/coq,herbelin/github-coq,ejgallego/coq,Zimmi48/coq,amintimany/coq,shindere/coq,maximedenes/coq,Zimmi48/coq,gares/coq,ppedrot/coq,mlasson/coq,letouzey/coq-wip,aspiwack/coq,Matafou/coq,ejgallego/coq,jpdeplaix/coq,william-lawvere/coq,coq/coq,gares/coq,ppedrot/coq,pirapira/coq2rust,coq/coq,barras/coq,coq/coq,8l/coq,Ptival/coq,mlasson/coq,aspiwack/coq,herbelin/github-coq,barras/coq,shindere/coq,Matafou/coq,gmalecha/coq,letouzey/coq-wip,coq/coq,TOSPIO/coq,TOSPIO/coq,Zimmi48/coq