8247860: Shenandoah: add update watermark line in rich assert failure message

Reviewed-by: rkennke

Author: shipilev

src/hotspot/share/gc/shenandoah/shenandoahAsserts.cpp

@@ -67,6 +67,7 @@ void ShenandoahAsserts::print_obj(ShenandoahMessageBuffer& msg, oop obj) {
 
   msg.append("  " PTR_FORMAT " - klass " PTR_FORMAT " %s\n", p2i(obj), p2i(obj->klass()), obj->klass()->external_name());
   msg.append("    %3s allocated after mark start\n", ctx->allocated_after_mark_start(obj) ? "" : "not");
+  msg.append("    %3s after update watermark\n",     cast_from_oop<HeapWord*>(obj) >= r->get_update_watermark() ? "" : "not");
   msg.append("    %3s marked \n",                    ctx->is_marked(obj) ? "" : "not");
   msg.append("    %3s in collection set\n",          heap->in_collection_set(obj) ? "" : "not");
   msg.append("  mark:%s\n", mw_ss.as_string());