Add FrontEndStrategy, ResolutionFrontEndStrategy and KernelFrontEndStrategy

tests/compiler/dart2js/kernel/impact_test.dart

Index: tests/compiler/dart2js/kernel/impact_test.dart
diff --git a/tests/compiler/dart2js/kernel/impact_test.dart b/tests/compiler/dart2js/kernel/impact_test.dart
index 91d8a7dd5fcaf639848200eea8d3f4eccd456bae..22f2ee5b9ad02bd23f3ac9406e9814ee5fc0b661 100644
--- a/tests/compiler/dart2js/kernel/impact_test.dart
+++ b/tests/compiler/dart2js/kernel/impact_test.dart
@@ -693,8 +693,9 @@ main(List<String> args) {
     compiler.resolution.retainCachesForTesting = true;
     Expect.isTrue(await compiler.run(entryPoint));
     JavaScriptBackend backend = compiler.backend;
-    KernelElementAdapter kernelElementAdapter =
-        new KernelWorldBuilder(compiler.reporter, backend.kernelTask.program);
+    KernelWorldBuilder kernelElementAdapter =
+        new KernelWorldBuilder(compiler.reporter);
+    kernelElementAdapter.addProgram(backend.kernelTask.program);
 
     checkLibrary(compiler, kernelElementAdapter, compiler.mainApp,
         fullTest: fullTest);