Extend thread-related debug messages.
Move finalizer closure to the end of objects.

* fnlz_mlc.c: Move finalizer closure for finalized object kinds to the end
of objects.  This way, we don't require all interior pointers, and GC_base
returns the expected address.
* tests/disclaim_test.c: Improve test coverage.
Remove closure data from GC_register_disclaim_proc.

* include/gc_disclaim.h, fnlz_mlc.c (GC_disclaim_proc, GC_register_disclaim_proc):
Remove CD from typedef and function.
* reclaim.c (GC_reclaim_uninit, GC_reclaim_block): Adjust calls.
* include/private/gc_priv.h, misc.c: Remove CD from object kind struct and
initializers.
Merge (dummy) remote-tracking branch 'paurkedal/finalizer-at-end'

Conflicts:
    fnlz_mlc.c
    tests/disclaim_test.c
Merge (dummy) remote-tracking branch 'paurkedal/remove-disclaim-cd'

Conflicts:
    include/private/gc_priv.h
Merge (dummy) remote-tracking branch 'paurkedal/t/thread_create_bug'

Conflicts:
    pthread_start.c
    pthread_support.c