Don't recreate CoreTypes in transformers. Pass it in.

pkg/kernel/test/baseline_tester.dart

Index: pkg/kernel/test/baseline_tester.dart
diff --git a/pkg/kernel/test/baseline_tester.dart b/pkg/kernel/test/baseline_tester.dart
index 81ab6c9561365f0b6b871c559e9fbe451df0a420..c3a0b5a43050080dd2ada7a4dfd3d50127308256 100644
--- a/pkg/kernel/test/baseline_tester.dart
+++ b/pkg/kernel/test/baseline_tester.dart
@@ -5,6 +5,7 @@ import 'dart:io';
 
 import 'package:analyzer/src/kernel/loader.dart';
 import 'package:kernel/application_root.dart';
+import 'package:kernel/core_types.dart';
 import 'package:kernel/kernel.dart';
 import 'package:kernel/target/targets.dart';
 import 'package:kernel/text/ast_to_text.dart';
@@ -25,8 +26,10 @@ abstract class TestTarget extends Target {
   Annotator get annotator => null;
 
   // Return a list of strings so that we can accumulate errors.
-  List<String> performModularTransformations(Program program);
-  List<String> performGlobalTransformations(Program program);
+  List<String> performModularTransformations(
+      CoreTypes coreTypes, Program program);
+  List<String> performGlobalTransformations(
+      CoreTypes coreTypes, Program program);
 }
 
 void runBaselineTests(String folderName, TestTarget target) {
@@ -45,6 +48,7 @@ void runBaselineTests(String folderName, TestTarget target) {
         String filenameOfCurrent = '$outputDirectory/$shortName.current.txt';
 
         var program = new Program();
+        var coreTypes = new CoreTypes(program);
         var loader = await batch.getLoader(
             program,
             new DartOptions(
@@ -55,9 +59,9 @@ void runBaselineTests(String folderName, TestTarget target) {
         loader.loadProgram(dartPath, target: target);
         verifyProgram(program);
         var errors = <String>[];
-        errors.addAll(target.performModularTransformations(program));
+        errors.addAll(target.performModularTransformations(coreTypes, program));
         verifyProgram(program);
-        errors.addAll(target.performGlobalTransformations(program));
+        errors.addAll(target.performGlobalTransformations(coreTypes, program));
         verifyProgram(program);
 
         var buffer = new StringBuffer();