Improve kernel events implementation (#430)

* Improve kernel events implementation

* Some cleanup

* Address PR feedback

Ryujinx.HLE/HOS/Kernel/KReadableEvent.cs

@@ -0,0 +1,62 @@
+namespace Ryujinx.HLE.HOS.Kernel
+{
+    class KReadableEvent : KSynchronizationObject
+    {
+        private KEvent Parent;
+
+        private bool Signaled;
+
+        public KReadableEvent(Horizon System, KEvent Parent) : base(System)
+        {
+            this.Parent = Parent;
+        }
+
+        public override void Signal()
+        {
+            System.CriticalSectionLock.Lock();
+
+            if (!Signaled)
+            {
+                Signaled = true;
+
+                base.Signal();
+            }
+
+            System.CriticalSectionLock.Unlock();
+        }
+
+        public KernelResult Clear()
+        {
+            Signaled = false;
+
+            return KernelResult.Success;
+        }
+
+        public KernelResult ClearIfSignaled()
+        {
+            KernelResult Result;
+
+            System.CriticalSectionLock.Lock();
+
+            if (Signaled)
+            {
+                Signaled = false;
+
+                Result = KernelResult.Success;
+            }
+            else
+            {
+                Result = KernelResult.InvalidState;
+            }
+
+            System.CriticalSectionLock.Unlock();
+
+            return Result;
+        }
+
+        public override bool IsSignaled()
+        {
+            return Signaled;
+        }
+    }
+}