* lisp/emacs-lisp/edebug.el: Use nadvice.
(edebug-original-read): Remove.
(edebug--read): Rename from edebug-read and add `orig' arg.
(edebug-uninstall-read-eval-functions)
(edebug-install-read-eval-functions): Use nadvice.
(edebug-read-sexp, edebug-read-storing-offsets, edebug-read-symbol)
(edebug-read-and-maybe-wrap-form1, edebug-instrument-callee)
(edebug-read-string, edebug-read-function): Use just `read'.
(edebug-original-debug-on-entry): Remove.
(edebug--debug-on-entry): Rename from edebug-debug-on-entry and add
`orig' arg.
(debug-on-entry): Override with nadvice.