Move solution and projects to src

src/Ryujinx.Common/ReferenceEqualityComparer.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Ryujinx.Common
+{
+    public class ReferenceEqualityComparer<T> : IEqualityComparer<T>
+        where T : class
+    {
+        public bool Equals(T x, T y)
+        {
+            return x == y;
+        }
+
+        public int GetHashCode([DisallowNull] T obj)
+        {
+            return obj.GetHashCode();
+        }
+    }
+}