Respect SYSTEM_EXT_ROOT in odrefresh am: 0a964610eb am: 79ba38e312

Original change: https://android-review.googlesource.com/c/platform/art/+/2225897

Change-Id: Iaa34f23e85129c237a7766c48308c91910e52393
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>