[GC] Reordered conditionals in gc_ms_get_free_object() in terms of descending likelihood, to reduce branches and help prediction in this hot path.
[GC] Reordered conditionals in gc_ms_get_free_object() in terms of descending
likelihood, to reduce branches and help prediction in this hot path.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@45208 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot