ART: Refactor abort code

Remove Runtime::Aborter and let Runtime::Abort set the abort message
on target.

This works around a missing tail-call optimization that leads to a
superfluous frame on the call-stack when aborting.

Partially reverts commit 3fec9ac0.

Bug: 62810360
Test: m test-art-host
Test: Manual inspection of abort dump
Change-Id: Ie4efc8bbdc8b665b23081b37a11921fe26b182b4