Fix a test to check duplicated phandles am: 718007765a am: bc2c5f2384

Original change: https://android-review.googlesource.com/c/platform/system/libufdt/+/2385752

Change-Id: Id9e3e33501130aba193bcbd7135e7d8b35b158ee
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>