Correctly handle setters in KernelWorldBuilder

tests/compiler/dart2js/kernel/closed_world2_test.dart

Index: tests/compiler/dart2js/kernel/closed_world2_test.dart
diff --git a/tests/compiler/dart2js/kernel/closed_world2_test.dart b/tests/compiler/dart2js/kernel/closed_world2_test.dart
index a18e859f1d14146a18aa4044366a8cad864f56e3..e3ece22d7fda2a26cf3180382c93bef28a353deb 100644
--- a/tests/compiler/dart2js/kernel/closed_world2_test.dart
+++ b/tests/compiler/dart2js/kernel/closed_world2_test.dart
@@ -126,6 +126,12 @@ main(List<String> args) {
         compiler.reporter, enqueuer2, worldBuilder.elementEnvironment);
     BackendUsage backendUsage2 = backendUsageBuilder2.close();
     checkBackendUsage(backendUsage1, backendUsage2, equivalence);
+
+    checkResolutionEnqueuers(backendUsage1, backendUsage2, enqueuer1, enqueuer2,
+        elementEquivalence: equivalence.entityEquivalence,
+        typeEquivalence: (ResolutionDartType a, DartType b) {
+      return equivalence.typeEquivalence(unalias(a), b);
+    }, elementFilter: elementFilter, verbose: arguments.verbose);
   });
 }