Improve to-space invariant error reporting in the CC collector.

In particular, distinguish references in an unused region from
the region space (which should never be encountered) from a
reference in a non-moving space.

Test: art/test/testrunner/testrunner.py
Bug: 72758079
Bug: 73004523
Change-Id: Iac632ae71dce9a36b33c14586eeb709dc2d7e7ce