patch 8.1.0700: using "gt" sometimes does not redraw a tab

Problem:    Using "gt" sometimes does not redraw a tab. (Jason Franklin)
Solution:   Always set must_redraw in redraw_all_later().

src/screen.c

@@ -238,6 +238,9 @@ redraw_all_later(int type)
     {
 	redraw_win_later(wp, type);
     }
+    // This may be needed when switching tabs.
+    if (must_redraw < type)
+	must_redraw = type;
 }
 
 /*

src/version.c

@@ -799,6 +799,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    700,
 /**/
     699,
 /**/