Refactor runtime into libraries, better type reps

test/codegen/expect/DeltaBlue.js

Index: test/codegen/expect/DeltaBlue.js
diff --git a/test/codegen/expect/DeltaBlue.js b/test/codegen/expect/DeltaBlue.js
index f528b619e12c3d02d3e0744516d93d93a4eb958c..18a33bb19e285c6a604e92e576a1e5765937f976 100644
--- a/test/codegen/expect/DeltaBlue.js
+++ b/test/codegen/expect/DeltaBlue.js
@@ -1,9 +1,11 @@
-dart.library('DeltaBlue', null, /* Imports */[
+dart_library.library('DeltaBlue', null, /* Imports */[
+  "dart_runtime/dart",
   'BenchmarkBase',
   'dart/core'
 ], /* Lazy imports */[
-], function(exports, BenchmarkBase, core) {
+], function(exports, dart, BenchmarkBase, core) {
   'use strict';
+  let dartx = dart.dartx;
   function main() {
     new DeltaBlue().report();
   }