Compile and run Hello World!

tests/compiler/dart2js/kernel/compiler_helper.dart

Index: tests/compiler/dart2js/kernel/compiler_helper.dart
diff --git a/tests/compiler/dart2js/kernel/compiler_helper.dart b/tests/compiler/dart2js/kernel/compiler_helper.dart
index ba8ab72306547dd7f9f109c313a4eac01fbf0e93..bea95fa6639836a1aff9e21f19ed168810017445 100644
--- a/tests/compiler/dart2js/kernel/compiler_helper.dart
+++ b/tests/compiler/dart2js/kernel/compiler_helper.dart
@@ -139,11 +139,8 @@ class MemoryDillLibraryLoaderTask extends DillLibraryLoaderTask {
   }
 }
 
-Future<Compiler> compileWithDill(
-    Uri entryPoint, Map<String, String> memorySourceFiles, List<String> options,
-    {bool printSteps: false,
-    CompilerOutput compilerOutput,
-    void beforeRun(Compiler compiler)}) async {
+Future createTemp(Uri entryPoint, Map<String, String> memorySourceFiles,
+    {bool printSteps: false}) async {
   if (memorySourceFiles.isNotEmpty) {
     Directory dir = await Directory.systemTemp.createTemp('dart2js-with-dill');
     if (printSteps) {
@@ -166,6 +163,16 @@ Future<Compiler> compileWithDill(
     '--platform=$buildDir/$configuration/patched_dart2js_sdk/platform.dill',
     '$entryPoint'
   ]);
+  return dillFile;
+}
+
+Future<Compiler> compileWithDill(
+    Uri entryPoint, Map<String, String> memorySourceFiles, List<String> options,
+    {bool printSteps: false,
+    CompilerOutput compilerOutput,
+    void beforeRun(Compiler compiler)}) async {
+  Uri dillFile =
+      await createTemp(entryPoint, memorySourceFiles, printSteps: printSteps);
 
   if (printSteps) {
     print('---- compile from dill $dillFile ---------------------------------');