bin/editorconfig-el: Fix test failure with snapshot (#384)

The tests don't like the "missing lexical-binding" warnings we get
from Emacs-31.  It's actually difficult to fix those warnings
because the `lexical-binding` cookie has to be on the first line
or on the second line but only if that second line starts with ";",
and I don't know of a way to satisfy those constraints are still have
a runnable shell script.

There are various possible workarounds, such as cutting the first few
lines before we pass the content of `$0` to Emacs, but it seemed
simpler to just stamp out the function that emits the warning.

Author: monnier

bin/editorconfig-el

@@ -1,7 +1,7 @@
 #!/bin/sh
-:;#-*-Emacs-Lisp-*-
+:;#-*- mode: emacs-lisp; lexical-binding:t -*-
 :;test -n "$EMACS_BIN" || EMACS_BIN=emacs
-:;exec "$EMACS_BIN" -batch -Q --eval '(setq debug-on-error t)' -l "$0" -- "$@"
+:;exec "$EMACS_BIN" -batch -Q --eval '(setq debug-on-error t internal--get-default-lexical-binding-function `always)' -l "$0" -- "$@"
 
 ;; editorconfig-el --- EditorConfig Core executable in Emacs Lisp