Method updateMaxDiff

tests/gpu/GPUUnitTest.h:135–142

        void retestSetup(size_t idx);

        inline void updateMaxDiff(float maxDiff, size_t idxDiff)
        {
            if (maxDiff > m_maxDiff)
            {
                m_maxDiff = maxDiff;
                m_idxDiff = idxDiff;
            }
        }
        inline float getMaxDiff() const
        {
            return m_maxDiff;