Individual simple tests such as CPUAccessToGPUMemoryTest are taking
several hours on emulators as the total amount of VRAM keeps increasing.
Limit the pool sizes to 2GB, only on emulator.
Change-Id: I4b33e8549f89413da255731e6748f606ca64a663
[ROCm/ROCR-Runtime commit: 588a5a2fd3]