[heap] Report newly found wrappers after deserialization

These wrappers wouldn't be found by the marker otherwise and are only
reported upon the next marking step or GC which potentially is already
too late; the embedder could've reclaimed those objects already.

BUG=chromium:717480

Review-Url: https://codereview.chromium.org/2860753003
Cr-Commit-Position: refs/heads/master@{#45094}

src/heap/heap.cc

@@ -4261,6 +4261,9 @@ void Heap::RegisterReservationsForBlackAllocation(Reservation* reservations) {
         }
       }
     }
+    // We potentially deserialized wrappers which require registering with the
+    // embedder as the marker will not find them.
+    local_embedder_heap_tracer()->RegisterWrappersWithRemoteTracer();
   }
 }