ART: Factor out stack dumping with monitor objects

Factor out generic stack walking with monitor object visitation into
MonitorObjectsStackVisitor. Rewrite StackDumpVisitor in terms of this,
removing Monitor::DescribeWait on the way.

Bug: 70538431
Test: m test-art-host
Test: manual (SIGQUIT dumping)
Change-Id: I6f359f9a5f665f308328ad466bc7a437f52aea24
4 files changed