Fix generate_hiddenapi_lists_test.py am: 2019bc53c2 am: f74d4b8da7

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1580530

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I5fb89e043e5ea788f0c30698a3465a82cc43d7c9