feat(library/type_context): do not cache whnf in tmp_mode if term contains metavariables
feat(library/type_context): do not cache whnf in tmp_mode if term contains metavariables

leanprover-community/lean,fpvandoorn/lean,leanprover/lean,leanprover-community/lean,dselsam/lean,Kha/lean,leanprover/lean,digama0/lean,Kha/lean,avigad/lean,fpvandoorn/lean,dselsam/lean,leanprover/lean,digama0/lean,johoelzl/lean,rlewis1988/lean,fpvandoorn/lean,leanprover/lean,leodemoura/lean,Kha/lean,rlewis1988/lean,avigad/lean,leodemoura/lean,rlewis1988/lean,johoelzl/lean,avigad/lean,johoelzl/lean,Kha/lean,leodemoura/lean,leodemoura/lean,digama0/lean,dselsam/lean,fpvandoorn/lean,dselsam/lean,leodemoura/lean,fpvandoorn/lean,digama0/lean,fpvandoorn/lean,leanprover-community/lean,rlewis1988/lean,Kha/lean,rlewis1988/lean,johoelzl/lean,avigad/lean,johoelzl/lean,dselsam/lean,Kha/lean,leodemoura/lean,dselsam/lean,leanprover-community/lean,avigad/lean,leanprover-community/lean,leanprover/lean,rlewis1988/lean,avigad/lean,leanprover-community/lean,johoelzl/lean,digama0/lean,digama0/lean,leanprover/lean