core: cpu_manager: Fix a typo in PreemptSingleCore, which broke many games.

- We were reload'ing the old current scheduler, which may have changed.

src/core/cpu_manager.cpp

@@ -254,29 +254,34 @@ void CpuManager::SingleCoreRunSuspendThread() {
 }
 
 void CpuManager::PreemptSingleCore(bool from_running_enviroment) {
-    std::size_t old_core = current_core;
-    auto& scheduler = system.Kernel().Scheduler(old_core);
-    Kernel::Thread* current_thread = scheduler.GetCurrentThread();
-    if (idle_count >= 4 || from_running_enviroment) {
-        if (!from_running_enviroment) {
-            system.CoreTiming().Idle();
-            idle_count = 0;
+    {
+        auto& scheduler = system.Kernel().Scheduler(current_core);
+        Kernel::Thread* current_thread = scheduler.GetCurrentThread();
+        if (idle_count >= 4 || from_running_enviroment) {
+            if (!from_running_enviroment) {
+                system.CoreTiming().Idle();
+                idle_count = 0;
+            }
+            current_thread->SetPhantomMode(true);
+            system.CoreTiming().Advance();
+            current_thread->SetPhantomMode(false);
         }
-        current_thread->SetPhantomMode(true);
-        system.CoreTiming().Advance();
-        current_thread->SetPhantomMode(false);
+        current_core.store((current_core + 1) % Core::Hardware::NUM_CPU_CORES);
+        system.CoreTiming().ResetTicks();
+        scheduler.Unload(scheduler.GetCurrentThread());
+
+        auto& next_scheduler = system.Kernel().Scheduler(current_core);
+        Common::Fiber::YieldTo(current_thread->GetHostContext(), next_scheduler.ControlContext());
     }
-    current_core.store((current_core + 1) % Core::Hardware::NUM_CPU_CORES);
-    system.CoreTiming().ResetTicks();
-    scheduler.Unload(scheduler.GetCurrentThread());
-    auto& next_scheduler = system.Kernel().Scheduler(current_core);
-    Common::Fiber::YieldTo(current_thread->GetHostContext(), next_scheduler.ControlContext());
-    /// May have changed scheduler
-    auto& current_scheduler = system.Kernel().Scheduler(current_core);
-    current_scheduler.Reload(scheduler.GetCurrentThread());
-    auto* currrent_thread2 = current_scheduler.GetCurrentThread();
-    if (!currrent_thread2->IsIdleThread()) {
-        idle_count = 0;
+
+    // May have changed scheduler
+    {
+        auto& scheduler = system.Kernel().Scheduler(current_core);
+        scheduler.Reload(scheduler.GetCurrentThread());
+        auto* currrent_thread2 = scheduler.GetCurrentThread();
+        if (!currrent_thread2->IsIdleThread()) {
+            idle_count = 0;
+        }
     }
 }