patch 8.1.1049: when user tries to exit with CTRL-C message is confusing

Problem:    When user tries to exit with CTRL-C message is confusing.
Solution:   Only mention ":qa!" when there is a changed buffer. (closes #4163)
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index 1224a3f..4c63bb8 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -1,5 +1,7 @@
 " Test for various Normal mode commands
 
+source shared.vim
+
 func Setup_NewWindow()
   10new
   call setline(1, range(1,100))
@@ -2542,3 +2544,13 @@
 
   %bwipeout!
 endfunc
+
+func Test_message_when_using_ctrl_c()
+  exe "normal \<C-C>"
+  call assert_match("Type  :qa  and press <Enter> to exit Vim", Screenline(&lines))
+  new
+  cal setline(1, 'hi!')
+  exe "normal \<C-C>"
+  call assert_match("Type  :qa!  and press <Enter> to abandon all changes and exit Vim", Screenline(&lines))
+  bwipe!
+endfunc