FROMLIST: selftests: futex: Use a 64-bit time_t am: 2cfedebbe1

Original change: https://android-review.googlesource.com/c/platform/external/linux-kselftest/+/2791624

Change-Id: I310100cdd86d9d7e7382643ea8c4bac13fa008c3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>