Optimize occur_evar_upto_types, avoiding repeateadly looking into the same evar.
Optimize occur_evar_upto_types, avoiding repeateadly looking into the
same evar.

ejgallego/coq,maximedenes/coq,SkySkimmer/coq,william-lawvere/coq,ppedrot/coq,gares/coq,ppedrot/coq,SkySkimmer/coq,gares/coq,Matafou/coq,mattam82/coq,mattam82/coq,Ptival/coq,william-lawvere/coq,coq/coq,ppedrot/coq,Lionel-Rieg/coq,JasonGross/coq,JasonGross/coq,Matafou/coq,amintimany/coq,Ptival/coq,letouzey/coq-wip,letouzey/coq-wip,herbelin/github-coq,maximedenes/coq,Zimmi48/coq,maximedenes/coq,letouzey/coq-wip,Ptival/coq,coq/coq,coq/coq,JasonGross/coq,Zimmi48/coq,SkySkimmer/coq,coq/coq,herbelin/github-coq,letouzey/coq-wip,mattam82/coq,maximedenes/coq,Matafou/coq,amintimany/coq,gares/coq,herbelin/github-coq,william-lawvere/coq,Lionel-Rieg/coq,SkySkimmer/coq,silene/coq,amintimany/coq,ejgallego/coq,ppedrot/coq,letouzey/coq-wip,gares/coq,maximedenes/coq,silene/coq,silene/coq,Zimmi48/coq,ejgallego/coq,Lionel-Rieg/coq,JasonGross/coq,ejgallego/coq,ppedrot/coq,Zimmi48/coq,gares/coq