patch 8.0.1449: slow redrawing with DirectX

Problem:    Slow redrawing with DirectX.
Solution:   Avoid calling gui_mch_flush() unnecessarily, especially when
            updating the cursor. (Ken Takata, closes #2560)
diff --git a/src/edit.c b/src/edit.c
index bf2cf31..9330a40 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -3451,7 +3451,7 @@
     compl_orig_text = NULL;
     compl_enter_selects = FALSE;
     /* clear v:completed_item */
-    set_vim_var_dict(VV_COMPLETED_ITEM, dict_alloc());
+    set_vim_var_dict(VV_COMPLETED_ITEM, dict_alloc_lock(VAR_FIXED));
 }
 
 /*
@@ -3553,8 +3553,7 @@
 	{
 	    /* Show the cursor after the match, not after the redrawn text. */
 	    setcursor();
-	    out_flush();
-	    gui_update_cursor(FALSE, FALSE);
+	    out_flush_cursor(FALSE, FALSE);
 	}
 #endif
 	compl_restarting = TRUE;
@@ -4704,7 +4703,7 @@
      * flicker, thus we can't do that. */
     changed_cline_bef_curs();
     /* clear v:completed_item */
-    set_vim_var_dict(VV_COMPLETED_ITEM, dict_alloc());
+    set_vim_var_dict(VV_COMPLETED_ITEM, dict_alloc_lock(VAR_FIXED));
 }
 
 /*
@@ -4724,7 +4723,7 @@
 
     /* Set completed item. */
     /* { word, abbr, menu, kind, info } */
-    dict = dict_alloc();
+    dict = dict_alloc_lock(VAR_FIXED);
     if (dict != NULL)
     {
 	dict_add_nr_str(dict, "word", 0L,
@@ -4936,8 +4935,7 @@
 	{
 	    /* Show the cursor after the match, not after the redrawn text. */
 	    setcursor();
-	    out_flush();
-	    gui_update_cursor(FALSE, FALSE);
+	    out_flush_cursor(FALSE, FALSE);
 	}
 #endif