* test/lisp/files-tests.el: Unify test names

* test/lisp/files-tests.el: Unify test names

* test/lisp/files-tests.el (files-tests-local-variables)
(files-tests-bug-18141, files-tests-make-temp-file-empty-prefix)
(files-tests-bug-21454)
(files-tests-save-buffers-kill-emacs--confirm-kill-processes)
(files-tests-read-file-in-~)
(files-tests-file-name-non-special--subprocess)
(files-tests-file-name-non-special--buffers)
(files-tests-insert-directory-wildcard-in-dir-p)
(files-tests-make-directory, files-tests-no-file-write-contents)
(files-tests-copy-directory, files-tests-abbreviated-home-dir):
Unify test names.