Trim maps after releasing the startup linear alloc. am: 8ce90803c9 am: 705973c81d am: 075eca621b

Original change: https://android-review.googlesource.com/c/platform/art/+/2426115

Change-Id: I693ac669143d1fc15ffa908f67bd5172fd0bd4ea
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>