Fix marks and hb_n_marks consistency when disclaim returns true

Fix marks and hb_n_marks consistency when disclaim returns true

* reclaim.c [ENABLE_DISCLAIM] (GC_disclaim_and_reclaim): When a
disclaim callback returns 1 to protect an object from being reclaimed,
mark it to skip it on repeated scans within the cycle. In particular,
this fixes sz*hhdr->hb_n_marks<=HBLKSIZE assertion failure due to
excessive increments of hb_n_marks.