Fix null dereference in SweepInterpreterCaches am: 6a05d70393 am: 731076f33b am: 27deab460b

Original change: https://android-review.googlesource.com/c/platform/art/+/2194755

Change-Id: I112907d454cea1ffb8ed96822305f06d69e4591a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>