[flexiglass] Fixes failing test after coroutine lib upgrade. am: b243fe5f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24211453



Change-Id: If3ba6575e8ed875abab6607ad61f1c9e58add8fb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>