patch 8.0.0447: getting font name does not work on X11

Problem:    Getting font name does not work on X11.
Solution:   Implement gui_mch_get_fontname() for X11.  Add more GUI tests.
            (Kazunobu Kuriyama)
diff --git a/Filelist b/Filelist
index 2aeea28..72a1f96 100644
--- a/Filelist
+++ b/Filelist
@@ -110,6 +110,7 @@
 		src/testdir/setup.vim \
 		src/testdir/gui_init.vim \
 		src/testdir/setup_gui.vim \
+		src/testdir/gui_preinit.vim \
 		src/testdir/test[0-9]*.ok \
 		src/testdir/test[0-9]*a.ok \
 		src/testdir/test_[a-z]*.ok \