Fix null dereference in SweepInterpreterCaches am: 6a05d70393 am: 731076f33b am: 27deab460b am: 92d2450a91 am: 4edab882c3

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

Change-Id: I0a66d0de3a543dc7d10b844d36ad8a05fe05f5ac
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>