Move some ObjPtr into Handle. am: 79fe23213e am: 4278f215e8 am: 496127f793 am: 26da7f27b4

Original change: https://android-review.googlesource.com/c/platform/art/+/2171607

Change-Id: I2766f753dab0452290a2689e60bb4cffcbd4cc80
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>