Move `reify` to use fasta instead of dartk

pkg/front_end/lib/src/fasta/testing/kernel_chain.dart

Index: pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
diff --git a/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart b/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
index bdb0ff71bacb40946129d9ee6bad1e44288a72db..3aae872d3e6b5bf6cce477a96a4d2796290c21dd 100644
--- a/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
+++ b/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
@@ -15,6 +15,8 @@ import 'dart:typed_data' show Uint8List;
 
 import 'package:kernel/kernel.dart' show loadProgramFromBinary;
 
+import 'package:kernel/target/targets.dart' show Target;
+
 import 'package:kernel/text/ast_to_text.dart' show Printer;
 
 import 'package:testing/testing.dart' show Result, StdioProcess, Step;
@@ -192,20 +194,28 @@ class Compile extends Step<TestDescription, Program, CompileContext> {
     }
 
     Uri sdk = await computePatchedSdk();
-    Program p = await kernelForProgram(
-        description.uri,
-        new CompilerOptions()
-          ..sdkRoot = sdk
-          ..packagesFileUri = Uri.base.resolve('.packages')
-          ..strongMode = context.strongMode
-          ..linkedDependencies = [sdk.resolve('platform.dill')]
-          ..onError = reportError);
+    var options = new CompilerOptions()
+      ..sdkRoot = sdk
+      ..compileSdk = true
+      ..packagesFileUri = Uri.base.resolve('.packages')
+      ..strongMode = context.strongMode
+      ..onError = reportError;
+    if (context.target != null) {
+      options.target = context.target;
+      // Do not link platform.dill, but recompile the platform libraries. This
+      // ensures that if target defines extra libraries that those get included
+      // too.
+    } else {
+      options.linkedDependencies = [sdk.resolve('platform.dill')];
+    }
+    Program p = await kernelForProgram(description.uri, options);
     return result ??= pass(p);
   }
 }
 
 abstract class CompileContext implements ChainContext {
   bool get strongMode;
+  Target get target;
 }
 
 class BytesCollector implements Sink<List<int>> {