Fix regression with multiple mode: entries in the prop line

* lisp/files.el (hack-local-variables--find-variables): Use the
final mode: line (which is the same as having several mode: bits
in the header line.

lisp/files.el

@@ -3900,7 +3900,7 @@ inhibited."
 	;; Note this is a no-op if enable-local-variables is nil.
 	(hack-dir-local-variables))
       (let ((result (append (hack-local-variables--find-variables handle-mode)
-                            (hack-local-variables-prop-line))))
+                            (hack-local-variables-prop-line handle-mode))))
         (if (and enable-local-variables
                  (not (inhibit-local-variables-p)))
             (progn

test/lisp/files-resources/file-mode-prop-line

@@ -0,0 +1 @@
+-*- mode: notexist; mode: text -*-

test/lisp/files-tests.el

@@ -1825,5 +1825,9 @@ Prompt users for any modified buffer with `buffer-offer-save' non-nil."
   (find-file (ert-resource-file "file-mode-multiple"))
   (should (eq major-mode 'outline-mode)))
 
+(ert-deftest files-test-set-mode-prop-line ()
+  (find-file (ert-resource-file "file-mode-prop-line"))
+  (should (eq major-mode 'text-mode)))
+
 (provide 'files-tests)
 ;;; files-tests.el ends here