Add method to wait for property to have given value. am: ac3d3e2d4f am: 7d62f81fb9 am: 4bc8ff28c6 am: 638df6cb1c am: 9a4316dfe5

Original change: https://android-review.googlesource.com/c/platform/system/librustutils/+/2584504

Change-Id: Ic1b43628fe04eea375b9aa96566f8aaea0aa7f3c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>