Bring js_model/model_test on par with compile_from_dill tests.

pkg/compiler/lib/src/js_model/js_strategy.dart

Index: pkg/compiler/lib/src/js_model/js_strategy.dart
diff --git a/pkg/compiler/lib/src/js_model/js_strategy.dart b/pkg/compiler/lib/src/js_model/js_strategy.dart
index d2e2caad4fc81aa1767174c3ebade8e0ff3e3e9b..82ac045a6c6965f690fe8c9e411d66169ce6c465 100644
--- a/pkg/compiler/lib/src/js_model/js_strategy.dart
+++ b/pkg/compiler/lib/src/js_model/js_strategy.dart
@@ -123,6 +123,9 @@ class JsBackendStrategy implements KernelBackendStrategy {
           uses.map(_map.toBackendClass).toSet();
     });
 
+    Iterable<MemberEntity> assignedInstanceMembers =
+        closedWorld.assignedInstanceMembers.map(_map.toBackendMember).toList();
+
     return new JsClosedWorld(_elementMap,
         elementEnvironment: _elementEnvironment,
         dartTypes: _elementMap.types,
@@ -135,9 +138,9 @@ class JsBackendStrategy implements KernelBackendStrategy {
         classSets: classSets,
         implementedClasses: implementedClasses,
         liveInstanceMembers: liveInstanceMembers,
+        assignedInstanceMembers: assignedInstanceMembers,
         // TODO(johnniwinther): Support these.
         allTypedefs: new ImmutableEmptySet<TypedefElement>(),
-        resolutionWorldBuilder: null,
         mixinUses: mixinUses,
         typesImplementedBySubclasses: null);
   }