Revert "[gfxstream] Use aemu SubAllocator for coherent memory"

It's desirable not to have a dependency on the AEMU
suballocator.

This reverts commit 16c7e8427376984ed87017cf91857d182c73967a.

BUG=421934218
TEST=CI

Change-Id: I04bbbd01713d0c1f5f4368d28c5e37ec9a46ce36
7 files changed