Bring js_model/model_test on par with compile_from_dill tests.

pkg/compiler/lib/src/universe/element_world_builder.dart

Index: pkg/compiler/lib/src/universe/element_world_builder.dart
diff --git a/pkg/compiler/lib/src/universe/element_world_builder.dart b/pkg/compiler/lib/src/universe/element_world_builder.dart
index 5e42fe51cbea216687756164caeeae712aaaea05..f076a436afa08d27ad2677534629d54867bdff05 100644
--- a/pkg/compiler/lib/src/universe/element_world_builder.dart
+++ b/pkg/compiler/lib/src/universe/element_world_builder.dart
@@ -183,9 +183,9 @@ class ElementResolutionWorldBuilder extends ResolutionWorldBuilderBase {
         nativeData: _nativeDataBuilder.close(),
         interceptorData: _interceptorDataBuilder.close(),
         backendUsage: _backendUsageBuilder.close(),
-        resolutionWorldBuilder: this,
         implementedClasses: _implementedClasses,
         liveInstanceMembers: _liveInstanceMembers,
+        assignedInstanceMembers: computeAssignedInstanceMembers(),
         allTypedefs: _allTypedefs,
         mixinUses: _mixinUses,
         typesImplementedBySubclasses: typesImplementedBySubclasses,