Remove unverifiable assertions from VisitRefsForCompaction am: b73e8ce972 am: f3300b5aea

Original change: https://android-review.googlesource.com/c/platform/art/+/2980792

Change-Id: Ifb128b44cb4b056d814aad6bf4905b8daf08bad1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>