Use lexical-binding in more tests

Use lexical-binding in more tests

* test/lib-src/emacsclient-tests.el:
* test/lisp/emacs-lisp/hierarchy-tests.el:
* test/lisp/eshell/eshell-tests.el:
* test/lisp/gnus/gnus-util-tests.el:
* test/lisp/progmodes/js-tests.el:
* test/lisp/textmodes/bibtex-tests.el:
* test/src/editfns-tests.el:
* test/src/fns-tests.el: Use lexical-binding.

* test/lisp/emacs-lisp/hierarchy-tests.el
(hierarchy-leafs-includes-lonely-roots):
* test/src/editfns-tests.el (transpose-test-get-byte-positions):
* test/src/fns-tests.el (fns-tests-func-arity):
Adjust for lexical-binding.