patch 8.0.1186: still quite a few old style tests

Problem:    Still quite a few old style tests.
Solution:   Convert old to new style tests. (Yegappan Lakshmanan)
            Avoid ringing the bell while running tests.
diff --git a/src/testdir/runtest.vim b/src/testdir/runtest.vim
index d07710a..245b51c 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -250,6 +250,9 @@
 
 " Execute the tests in alphabetical order.
 for s:test in sort(s:tests)
+  " Silence, please!
+  set belloff=all
+
   call RunTheTest(s:test)
 
   if len(v:errors) > 0 && index(s:flaky, s:test) >= 0