Fix an exponential behavior in guard checker for cofixpoints.
Fix an exponential behavior in guard checker for cofixpoints.

I had introduced it by mistake due to my OCaml dyslexia :)
Thanks to Enrico and Arnaud for saving my day!

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