Rename our allocator into allocator.ranchu am: 2d82337618

Original change: https://android-review.googlesource.com/c/device/generic/goldfish-opengl/+/2431554

Change-Id: I7a0c04d6ce3a19069eedda976d1f661f36b72e7c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>