patch 8.0.0489: clipboard and "* register is not tested

Problem:    Clipboard and "* register is not tested.
Solution:   Add a test for Mac and X11. (Kazunobu Kuriyama)
diff --git a/src/testdir/runtest.vim b/src/testdir/runtest.vim
index 1d694b5..0256d48 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -228,6 +228,7 @@
       \ 'Test_pipe_through_sort_all()',
       \ 'Test_pipe_through_sort_some()',
       \ 'Test_quoteplus()',
+      \ 'Test_quotestar()',
       \ 'Test_reltime()',
       \ ]