CPU_Manager: Correct stopping on SingleCore.

src/core/cpu_manager.cpp

@@ -39,10 +39,15 @@ void CpuManager::Initialize() {
 void CpuManager::Shutdown() {
     running_mode = false;
     Pause(false);
+    if (is_multicore) {
         for (std::size_t core = 0; core < Core::Hardware::NUM_CPU_CORES; core++) {
             core_data[core].host_thread->join();
             core_data[core].host_thread.reset();
         }
+    } else {
+        core_data[0].host_thread->join();
+        core_data[0].host_thread.reset();
+    }
 }
 
 std::function<void(void*)> CpuManager::GetGuestThreadStartFunc() {