Use lexical-binding by default for M-:, --eval, and *scratch*

Use lexical-binding by default for M-:, --eval, and *scratch*

* lisp/startup.el (command-line): Default to lexical-binding in *scratch*.
(normal-no-mouse-startup-screen, command-line-1):
Use startup--get-buffer-create-scratch.
(command-line-1):
* lisp/simple.el (eval-expression):
* lisp/server.el (server-eval-and-print): Use lexical-binding to
evaluate the expression.
(server-execute): Use startup--get-buffer-create-scratch.
* lisp/ielm.el (inferior-emacs-lisp-mode): Default to lexical-binding.