Crash on "Saving world" when F3+L profiling is active - java.lang.NullPointerException: Cannot read field "f" because "this.D" is null

Steps to reproduce:
1. Start Minecraft.
2. Create a new world or join a world.
3. Press F3+L.
4. Before the 10 seconds are up, exit the world by pressing Escape then clicking "Save and Quit to Title".
5. Notice the resulting crash.