Fix reference model memory leaks for the following ops

- OpClamp
- OpArithmeticRightShift
- OpMul
- OpTable
- OpTranspose

Signed-off-by: Jerry Ge <jerry.ge@arm.com>
Change-Id: Icb84a8a17c298b471a635310454775977a9133cb
diff --git a/reference_model/src/ops/activation_funcs.h b/reference_model/src/ops/activation_funcs.h
index 4853971..9a697cd 100644
--- a/reference_model/src/ops/activation_funcs.h
+++ b/reference_model/src/ops/activation_funcs.h
@@ -1,5 +1,5 @@
 
-// Copyright (c) 2020, ARM Limited.
+// Copyright (c) 2020-2022, ARM Limited.
 //
 //    Licensed under the Apache License, Version 2.0 (the "License");
 //    you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@
         INIT_ATTRIBUTE(Clamp);
         register_fcn();
     }
+    virtual ~OpClamp();
     static constexpr int32_t QMin = GetQMin<Dtype>::value;
     static constexpr int32_t QMax = GetQMax<Dtype>::value;
     using InEigenType             = typename GetEigenType<Dtype>::type;