patch 9.0.1324: "gj" and "gk" do not move correctly over a closed fold

Problem:    "gj" and "gk" do not move correctly over a closed fold.
Solution:   Use the same code as used for "j"/"k" to go to the next/previous
            line. (Luuk van Baal, closes #12007)
diff --git a/src/testdir/test_fold.vim b/src/testdir/test_fold.vim
index a35ea1e..e0119c4 100644
--- a/src/testdir/test_fold.vim
+++ b/src/testdir/test_fold.vim
Binary files differ