Fix ref proxy casting

Author: yck1509

Confuser.Runtime/RefProxy.Strong.cs

@@ -63,7 +63,7 @@ internal static void Initialize(RuntimeFieldHandle field, byte opKey) {
 					code[index++] = (byte)i;
 
 					var mType = mIndex == -1 ? method.DeclaringType : mParams[mIndex].ParameterType;
-					if (!mType.IsValueType) {
+					if (mType.IsClass && !(mType.IsPointer || mType.IsByRef)) {
 						var cToken = info.GetTokenFor(mType.TypeHandle);
 						code[index++] = 0x74;
 						code[index++] = (byte)cToken;