patch 8.0.0522: Win32: when 'clipboard' is "unnamed" yyp does not work

Problem:    MS-Windows: when 'clipboard' is "unnamed" yyp does not work in a
            :global command.
Solution:   When setting the clipboard was postponed, do not clear the
            register.
diff --git a/src/ops.c b/src/ops.c
index 9cff1bc..7cbc0c2 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -6466,7 +6466,7 @@
 	VIsual = old_visual;
 	VIsual_mode = old_visual_mode;
     }
-    else
+    else if (!is_clipboard_needs_update())
     {
 	clip_free_selection(cbd);