Skip allocation subtests that allocate too much VA

Skip allocation subtests that allocate too much VA

For 32-bit builds of CTS we can't allocate more host visible
memory than there is virtual address space for the process
since the allocation will fail and cause a false negative
result.

This CL skips over host visible allocations that would add
up to more than 1.5GB of virtual address space. This can
happen on platforms that expose very large heaps that
support memory types that include host visible memory.
The implementation can't cap the available memory size
since the heap can support allocations of memory other
than host visible and it doesn't want to restrict those
that don't consume CPU virtual address space. Its up
to CTS to limit how much virtual address space it
chooses to allocate.

Affects:
dEQP-VK.memory.allocation.basic.percent_1.*.count_12

Components: Vulkan

VK-GL-CTS issue: 859

Change-Id: I321f5cad567245571722f53397df26e23a4cee97