No longer store the compilation-context in WorkItem.

tests/compiler/dart2js/compiler_helper.dart

Index: tests/compiler/dart2js/compiler_helper.dart
diff --git a/tests/compiler/dart2js/compiler_helper.dart b/tests/compiler/dart2js/compiler_helper.dart
index cff4c52bfe78b9d060beb5da3043b0b2d0e7531e..7c7746389885381aacbbd4ed3e6da7c44426f7b4 100644
--- a/tests/compiler/dart2js/compiler_helper.dart
+++ b/tests/compiler/dart2js/compiler_helper.dart
@@ -82,12 +82,9 @@ Future<String> compile(String code,
     compiler.processQueue(compiler.enqueuer.resolution, element);
     compiler.world.populate();
     compiler.backend.onResolutionComplete();
-    var context = new js.JavaScriptItemCompilationContext();
-    ResolutionWorkItem resolutionWork =
-        new ResolutionWorkItem(element, context);
+    ResolutionWorkItem resolutionWork = new ResolutionWorkItem(element);
     resolutionWork.run(compiler, compiler.enqueuer.resolution);
-    CodegenWorkItem work =
-        new CodegenWorkItem(compiler, element, context);
+    CodegenWorkItem work = new CodegenWorkItem(compiler, element);
     compiler.phase = Compiler.PHASE_COMPILING;
     work.run(compiler, compiler.enqueuer.codegen);
     js.JavaScriptBackend backend = compiler.backend;