Don't switch to blank NAND in the middle of emulation

Switching to blank NAND when emulation is running is an extremely bad
idea. It's akin to opening up a Wii and replacing the NAND chip while
you're playing a game on it.

Except we're not even replacing it with a NAND that has the same
contents. The blank NAND has nothing in it except the save file for
the current game, which is likely to result in the emulated software
getting inconsistent results and possibly even crashing depending on
how it caches title information.

An example of games that check the saves for other games is
Mario Kart Wii -- it checks the filesystem for Super Mario Galaxy saves
to decide whether to unlock characters. With this 'switch NAND
while emulation is active' misfeature, this will likely break.
And that's the main problem: it encourages sloppy emulation and no one
really knows how many things it can break.

Just don't let the user do horrible things like that during emulation.
If they want to use a blank NAND, they can do so by starting input
recording before launching a game. It's likely they will want to do
this if they plan to share their DTM anyway.

Source/Core/Core/Core.cpp

@@ -903,10 +903,6 @@ void UpdateWantDeterminism(bool initial)
       // We need to clear the cache because some parts of the JIT depend on want_determinism,
       // e.g. use of FMA.
       JitInterface::ClearCache();
-
-      // Don't call InitializeWiiRoot during boot, because IOS already does it.
-      if (!initial)
-        Core::InitializeWiiRoot(s_wants_determinism);
     });
   }
 }