(byte-compile-maybe-guarded): Make its code edebuggable

(byte-compile-maybe-guarded): Make its code edebuggable

* lisp/emacs-lisp/bytecomp.el (byte-compile--reify-function): Hoist
subexpression out of `if`.
(byte-compile-variadic-numeric, byte-compile--cond-vars)
(byte-compile--cond-switch-prefix, byte-compile-file-form-defalias):
Obey `lexical-binding` when evaluating the code we're compiling.
(byte-compile--maybe-guarded): New function, extracted from
`byte-compile-maybe-guarded`.
(byte-compile-maybe-guarded): Use it so we can edebug the code.

(cherry picked from commit c26862a6c9f2d46f41b4f91972d139a138cb2edf)