Add 'safety' function declaration

Add 'safety' function declaration

* lisp/emacs-lisp/comp.el (comp-known-predicates): Use
'comp-func-safety'.
(comp-ctxt, comp-mvar-type-hint-match-p): New 'safety' slot.
(comp-c-func-name): New function.
(comp--spill-lap-function, comp--intern-func-in-ctxt): Update.
* lisp/emacs-lisp/bytecomp.el (byte-compile-from-buffer): Spill safety.
* lisp/emacs-lisp/byte-run.el (byte-run--set-completion): New alias.
(defun-declarations-alist): Update.