patch 8.2.0369: various Normal mode commands not fully tested

Problem:    Various Normal mode commands not fully tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5751)
diff --git a/src/testdir/test_excmd.vim b/src/testdir/test_excmd.vim
index c594548..a0645e8 100644
--- a/src/testdir/test_excmd.vim
+++ b/src/testdir/test_excmd.vim
@@ -57,6 +57,10 @@
   1,3copy 2
   call assert_equal(['L1', 'L2', 'L1', 'L2', 'L3', 'L3', 'L4'], getline(1, 7))
 
+  " Specifying a count before using : to run an ex-command
+  exe "normal! gg4:yank\<CR>"
+  call assert_equal("L1\nL2\nL1\nL2\n", @")
+
   close!
 endfunc