patch 8.0.1787: cannot insert the whole cursor line

Problem:    Cannot insert the whole cursor line.
Solution:   Make CTRL-R CTRL-L work. (Andy Massimino, closes #2857)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index ff0756c..a79f276 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -306,6 +306,9 @@
   call feedkeys("ft:aaa \<C-R>\<C-F> bbb\<C-B>\"\<CR>", 'tx')
   call assert_equal('"aaa /tmp/some bbb', @:)
 
+  call feedkeys(":aaa \<C-R>\<C-L> bbb\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"aaa '.getline(1).' bbb', @:)
+
   set incsearch
   call feedkeys("fy:aaa veryl\<C-R>\<C-W> bbb\<C-B>\"\<CR>", 'tx')
   call assert_equal('"aaa verylongword bbb', @:)