patch 9.0.0310: output of :messages dissappears when cmdheight is zero

Problem:    Output of :messages dissappears when cmdheight is zero.
Solution:   Do not use the messages window for :messages.  Make Esc close the
            messages window.

src/message.c

@@ -1077,6 +1077,7 @@ ex_messages(exarg_T *eap)
     }
 
     msg_hist_off = TRUE;
+    dont_use_message_window();
 
     p = first_msg_hist;
     if (eap->addr_count != 0)

src/normal.c

@@ -6820,7 +6820,14 @@ nv_esc(cmdarg_T *cap)
 	redraw_curbuf_later(UPD_INVERTED);
     }
     else if (no_reason)
-	vim_beep(BO_ESC);
+    {
+#ifdef HAS_MESSAGE_WINDOW
+	if (popup_message_win_visible())
+	    popup_hide_message_win();
+	else
+#endif
+	    vim_beep(BO_ESC);
+    }
     clearop(cap->oap);
 
     // A CTRL-C is often used at the start of a menu.  When 'insertmode' is

src/version.c

@@ -707,6 +707,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    310,
 /**/
     309,
 /**/