Revert 3b0f23792 "Distinguish C-m from RET"

Unpredictably hijacks C-m in some cases, which is unacceptable. A better
solution is needed.

core/core-keybinds.el

@@ -56,16 +56,6 @@ and Emacs states, and for non-evil users.")
                      (not (or (numberp key) (null key))))))
             [C-i] [?\C-i])))
 
-;; HACK Fixes Emacs' disturbing inability to distinguish C-m from RET. We don't
-;;      need the same hacks as C-i because *nobody* binds keys to C-m otherwise.
-(define-key key-translation-map [?\C-m]
-  (cmd! (if (let ((keys (this-single-command-raw-keys)))
-              (and keys
-                   (not (cl-position 'return keys))
-                   (not (cl-position 'kp-return keys))
-                   (display-graphic-p)))
-            [C-m] [?\C-m])))
-
 
 ;;
 ;;; Universal, non-nuclear escape