Merge "libcutils: clean up the ashmem code a bit." into main am: 88cb60c8d2

Original change: https://android-review.googlesource.com/c/platform/system/core/+/3506451

Change-Id: I5b032486c5a55b3374cdfedf568b0d4666d0b863
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>