Move some general utility lemmas from TypingWf to All_Forall#913

JasonGross wants to merge 1 commit intoMetaRocq:coq-8.16MetaRocq/metarocq:coq-8.16from

JasonGross:coq-8.16+refactor-all-typingwfJasonGross/metacoq:coq-8.16+refactor-all-typingwfCopy head branch name to clipboard