[T] Drop unused InstanceCounter.

Tests/InstanceCounter.h

-/**
- * \copyright
- * Copyright (c) 2012-2019, OpenGeoSys Community (http://www.opengeosys.org)
- *            Distributed under a Modified BSD License.
- *              See accompanying file LICENSE.txt or
- *              http://www.opengeosys.org/project/license
- *
- */
-
-#pragma once
-
-template <class T>
-class InstanceCounter
-{
-public:
-    InstanceCounter() {
-        ++_num_constructed;
-    }
-    InstanceCounter(InstanceCounter<T> const& /*unused*/) { ++_num_copied; }
-    InstanceCounter(InstanceCounter<T>&& /*unused*/) { ++_num_moved; }
-    virtual ~InstanceCounter() {
-        ++_num_destroyed;
-    }
-
-    static int getNumberOfConstructions() { return _num_constructed; }
-    static int getNumberOfCopies() { return _num_copied; }
-    static int getNumberOfMoves() { return _num_moved; }
-    static int getNumberOfDestructions() { return _num_destroyed; }
-    static int getNumberOfInstances()
-    {
-        return _num_constructed + _num_moved + _num_copied - _num_destroyed;
-    }
-
-    static void update(int& num_const, int& num_move, int& num_copy, int& num_inst)
-    {
-        num_const = getNumberOfConstructions();
-        num_move = getNumberOfMoves();
-        num_copy = getNumberOfCopies();
-        num_inst = getNumberOfInstances();
-    }
-
-private:
-    static int _num_constructed;
-    static int _num_copied;
-    static int _num_moved;
-    static int _num_destroyed;
-};
-
-template <class T>
-int InstanceCounter<T>::_num_constructed = 0;
-template <class T>
-int InstanceCounter<T>::_num_copied = 0;
-template <class T>
-int InstanceCounter<T>::_num_moved = 0;
-template <class T>
-int InstanceCounter<T>::_num_destroyed = 0;
-
-#define EXPECT_INSTANCES(type, num_const, num_move, num_copy, num_inst)        \
-    EXPECT_EQ((num_const), InstanceCounter<type>::getNumberOfConstructions()); \
-    EXPECT_EQ((num_move), InstanceCounter<type>::getNumberOfMoves());          \
-    EXPECT_EQ((num_copy), InstanceCounter<type>::getNumberOfCopies());         \
-    EXPECT_EQ((num_inst), InstanceCounter<type>::getNumberOfInstances())
-
-#define UPDATE_INSTANCES(type, num_const, num_move, num_copy, num_inst) \
-    (num_const) = InstanceCounter<type>::getNumberOfConstructions();    \
-    (num_move) = InstanceCounter<type>::getNumberOfMoves();             \
-    (num_copy) = InstanceCounter<type>::getNumberOfCopies();            \
-    (num_inst) = InstanceCounter<type>::getNumberOfInstances()