Cleanup resource loading of the VM.

runtime/bin/main.cc

Index: runtime/bin/main.cc
diff --git a/runtime/bin/main.cc b/runtime/bin/main.cc
index b9bc365f3cfb0f4b3ba54e94b1be0d859f29238a..941aafee5d8c1e899afee4a5c6a929fa0ec02559 100644
--- a/runtime/bin/main.cc
+++ b/runtime/bin/main.cc
@@ -598,10 +598,9 @@ static Dart_Isolate CreateIsolateAndSetupHelper(const char* script_uri,
   result = DartUtils::LoadScript(isolate_data->script_url, builtin_lib);
   CHECK_RESULT(result);
 
-  if (Dart_IsVMFlagSet("load_async")) {
-    result = Dart_RunLoop();
-    CHECK_RESULT(result);
-  }
+  // Run event-loop and wait for script loading to complete.
+  result = Dart_RunLoop();
+  CHECK_RESULT(result);
 
   Platform::SetPackageRoot(package_root);
   Dart_Handle io_lib_url = DartUtils::NewString(DartUtils::kIOLibURL);