Merge branch 'mem-random-div-zero' into 'master'

Merge branch 'mem-random-div-zero' into 'master'

Fix division by zero in random memory allocation test

I got a division by 0 with some configuration when running some random memory allocation tests.

The related code is:

    const VkDeviceSize		size	= 1 + (rng.getUint64() % ((m_heap.size / MAX_MEMORY_USAGE_DIV) - m_usage - 1));

It's possible for "(m_heap.size / MAX_MEMORY_USAGE_DIV) - m_usage - 1" to be equal to zero since we are doing a -1 and the method "full" just compare "m_usage * MAX_MEMORY_USAGE_DIV >= m_heap.size".

With this change I do a max(1) which should resolve the issue

See merge request !228