patch 9.0.0317: when updating the whole screen a popup may not be redrawn

Problem:    When updating the whole screen a popup may not be redrawn.
Solution:   Mark the screen and windows for redraw also when not clearing.
            Also mark popup windows for redraw.

src/popupwin.c

@@ -1937,6 +1937,20 @@ popup_terminal_exists(void)
 }
 #endif
 
+/*
+ * Mark all popup windows in the current tab and global for redrawing.
+ */
+    void
+popup_redraw_all(void)
+{
+    win_T	*wp;
+
+    FOR_ALL_POPUPWINS(wp)
+	wp->w_redr_type = UPD_NOT_VALID;
+    FOR_ALL_POPUPWINS_IN_TAB(curtab, wp)
+	wp->w_redr_type = UPD_NOT_VALID;
+}
+
 /*
  * Set the color for a notification window.
  */