Thread scheduler rewrite (#393)

* Started to rewrite the thread scheduler

* Add a single core-like scheduling mode, enabled by default

* Clear exclusive monitor on context switch

* Add SetThreadActivity, misc fixes

* Implement WaitForAddress and SignalToAddress svcs, misc fixes

* Misc fixes (on SetActivity and Arbiter), other tweaks

* Rebased

* Add missing null check

* Rename multicore key on config, fix UpdatePriorityInheritance

* Make scheduling data MLQs private

* nit: Ordering

Ryujinx.HLE/HOS/Kernel/KCoreContext.cs

@@ -0,0 +1,67 @@
+using System;
+
+namespace Ryujinx.HLE.HOS.Kernel
+{
+    class KCoreContext
+    {
+        private KScheduler Scheduler;
+
+        private HleCoreManager CoreManager;
+
+        public bool ContextSwitchNeeded { get; private set; }
+
+        public KThread CurrentThread  { get; private set; }
+        public KThread SelectedThread { get; private set; }
+
+        public KCoreContext(KScheduler Scheduler, HleCoreManager CoreManager)
+        {
+            this.Scheduler   = Scheduler;
+            this.CoreManager = CoreManager;
+        }
+
+        public void SelectThread(KThread Thread)
+        {
+            SelectedThread = Thread;
+
+            if (Thread != null)
+            {
+                Thread.LastScheduledTicks = (uint)Environment.TickCount;
+            }
+
+            ContextSwitchNeeded = true;
+        }
+
+        public void UpdateCurrentThread()
+        {
+            ContextSwitchNeeded = false;
+
+            CurrentThread = SelectedThread;
+        }
+
+        public void ContextSwitch()
+        {
+            ContextSwitchNeeded = false;
+
+            if (CurrentThread != null)
+            {
+                CoreManager.GetThread(CurrentThread.Context.Work).Reset();
+            }
+
+            CurrentThread = SelectedThread;
+
+            if (CurrentThread != null)
+            {
+                CurrentThread.ClearExclusive();
+
+                CoreManager.GetThread(CurrentThread.Context.Work).Set();
+
+                CurrentThread.Context.Execute();
+            }
+        }
+
+        public void RemoveThread(KThread Thread)
+        {
+            //TODO.
+        }
+    }
+}