Fix `ClassLinker::AppendToBootClassPath` usages. am: 28451dc192 am: 678b965707

Original change: https://android-review.googlesource.com/c/platform/art/+/2196996

Change-Id: I8b82cbaa5f02351d1f4d558ec8008e0fe6dc63ce
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>