patch 8.0.1482: using feedkeys() does not work to test completion

Problem:    Using feedkeys() does not work to test Insert mode completion.
            (Lifepillar)
Solution:   Do not check for typed keys when executing :normal or feedkeys().
            Fix thesaurus completion not working when 'complete' is empty.
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index 6250c1b..d121aff 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -693,7 +693,7 @@
   norm! gt
   call assert_equal(0, &previewwindow)
   norm! gT
-  call assert_equal(12, tabpagenr('$'))
+  call assert_equal(10, tabpagenr('$'))
   tabonly
   pclose
   augroup MyBufAdd