DrmHalTest: null check for skipped test am: 9049fc93a8 am: 6f60eece49 am: 7eebef2366 am: 7dbaedfcb0

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2417394

Change-Id: Id88774f654e4b3e3f5f2240017e0e1ee04a1bd38
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>