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

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

Change-Id: I6f89ecacc02f0112c7bcd2765c13274f2805df2f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>