Add basic heap corruption detection ConcurrentCopying::Copy

Detect objects that have a null class. This also detects objects that
are not in the from-space allocated area since this area is zero
initialized.

Test: test-art-host

Bug: 37683299
Bug: 12687968
Bug: 37187694

(cherry picked from commit 350cf8a4)

Change-Id: I3ce282d3d3e523ca3952f85573fb03c1597b6bfc