player: make quit exit immediately

Stopping playback canceled waiting, but executed the remainder of the
playloop, including things like executing pointless seeks.

player/playloop.c

@@ -940,8 +940,10 @@ void run_playloop(struct MPContext *mpctx)
 
     }
 
+    handle_loop_file(mpctx);
+
     if (mpctx->stop_play)
-        mpctx->sleeptime = 0;
+        return;
 
     handle_osd_redraw(mpctx);
 
@@ -960,8 +962,6 @@ void run_playloop(struct MPContext *mpctx)
 
     handle_sstep(mpctx);
 
-    handle_loop_file(mpctx);
-
     handle_chapter_change(mpctx);
 
     handle_force_window(mpctx, false);