patch 8.1.0516: :move command marks buffer modified when nothing changed

Problem:    :move command marks buffer modified when nothing changed.
Solution:   Do not set 'modified'.  Add a test. (Jason Franklin)
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index 3a0c6e0..be66512 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -41,6 +41,7 @@
 source test_menu.vim
 source test_messages.vim
 source test_modeline.vim
+source test_move.vim
 source test_partial.vim
 source test_popup.vim
 source test_put.vim