Remove unneeded art::Unit member functions am: 6ff274b4a0 am: f8a005ef84 am: 5e77a4ec74 am: c4b1ccf814

Original change: https://android-review.googlesource.com/c/platform/art/+/2200113

Change-Id: Ib59be69f6b1cfc6afa2a3cb23ee9f7ab1fdd62cd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>