Speed up computing proof using for Admitted when trivial
Speed up computing proof using for Admitted when trivial

- when not in section, there is never anything to do.
- when in section but Unset Keep Admitted Variables, also skip evar
- normalizing the proof.

Fix #15858 ?

SkySkimmer/coq,ejgallego/coq,Zimmi48/coq,coq/coq,Zimmi48/coq,ejgallego/coq,ejgallego/coq,SkySkimmer/coq,coq/coq,coq/coq,Zimmi48/coq,Zimmi48/coq,SkySkimmer/coq,coq/coq,SkySkimmer/coq,ejgallego/coq