core: Partially persist emulation state across game boots.

src/tests/core/core_timing.cpp

@@ -40,9 +40,6 @@ struct ScopeInit final {
         core_timing.SetMulticore(true);
         core_timing.Initialize([]() {});
     }
-    ~ScopeInit() {
-        core_timing.Shutdown();
-    }
 
     Core::Timing::CoreTiming core_timing;
 };