* lisp/emacs-lisp/edebug.el (eval-defun): Simplify

* lisp/emacs-lisp/edebug.el (eval-defun): Simplify

(edebug-all-defs, edebug-all-forms): Don't autoload since the problem
it was working around has been fixed a while back.
(edebug--eval-defun): Rename from `edebug-eval-defun` and simplify by
making it an `:around` advice.
(edebug-install-read-eval-functions)
(edebug-uninstall-read-eval-functions): Adjust accordingly.
(edebug-eval-defun): Redefine as an obsolete wrapper.

* lisp/progmodes/elisp-mode.el (elisp--eval-defun):
Use `load-read-function` so it obeys `edebug-all-(defs|forms)`.
(elisp--eval-defun): Fix recent regression introduced with
`elisp--eval-defun-result`.