Revert "Android: Temporarily disable host thread check"

This reverts commit 361171fce0.

Source/Core/Core/Core.cpp

@@ -796,10 +796,7 @@ void SaveScreenShot(std::string_view name)
 static bool PauseAndLock(Core::System& system, bool do_lock, bool unpause_on_unlock)
 {
   // WARNING: PauseAndLock is not fully threadsafe so is only valid on the Host Thread
-// TODO: Fix Android
-#ifndef ANDROID
   ASSERT(IsHostThread());
-#endif
 
   if (!IsRunningAndStarted())
     return true;