Remove serializer whitelisting for 'dart:collection'

runtime/vm/raw_object_snapshot.cc

Index: runtime/vm/raw_object_snapshot.cc
diff --git a/runtime/vm/raw_object_snapshot.cc b/runtime/vm/raw_object_snapshot.cc
index d99d9433a1646c9cdff2249bd326b081c7a5b3fa..27ec70df7f8bf49e65ec7b0e3f029a72bf6df90a 100644
--- a/runtime/vm/raw_object_snapshot.cc
+++ b/runtime/vm/raw_object_snapshot.cc
@@ -116,8 +116,6 @@ void RawClass::WriteTo(SnapshotWriter* writer,
     SnapshotWriterVisitor visitor(writer);
     visitor.VisitPointers(from(), to());
   } else {
-    // Until we have maps implemented as internal VM objects we will use
-    // the collections library qualifier to allow maps to be sent across.
     if (writer->can_send_any_object() ||
         writer->AllowObjectsInDartLibrary(ptr()->library_)) {
       writer->WriteClassId(this);