Set lexical-binding in clojure-mode-font-lock-test.el

Must have been moved to the second line by a well-meaning fill operation.
Unfortunately, it has no effect on the second line and the tests broke on
buttercup 1.34.

Author: snogge

test/clojure-mode-font-lock-test.el

@@ -1,5 +1,4 @@
-;;; clojure-mode-font-lock-test.el --- Clojure Mode: Font lock test suite
-;; -*- lexical-binding: t; -*-
+;;; clojure-mode-font-lock-test.el --- Clojure Mode: Font lock test suite -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2014-2021 Bozhidar Batsov <[email protected]>