Add SExpression test and share tests between dart2dart and analyzer2dart.

tests/compiler/dart2js/backend_dart/sexpr2_test.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// Unittest test of the CPS ir generated by the dart2dart compiler.
+library dart_backend.sexpr2_test;
+
+import 'package:compiler/implementation/dart2jslib.dart';
+import 'package:compiler/implementation/cps_ir/cps_ir_nodes_sexpr.dart';
+import 'package:expect/expect.dart';
+
+import '../../../../pkg/analyzer2dart/test/test_helper.dart';
+import '../../../../pkg/analyzer2dart/test/sexpr_data.dart';
+
+import 'test_helper.dart';
+
+main() {
+  performTests(TEST_DATA, asyncTester, (TestSpec result) {
+    return compilerFor(result.input).then((Compiler compiler) {
+      String expectedOutput = result.output.trim();
+      String output = compiler.irBuilder.getIr(compiler.mainFunction)
+          .accept(new SExpressionStringifier()).trim();
+      Expect.equals(expectedOutput, output,
+          '\nInput:\n${result.input}\n'
+          'Expected:\n$expectedOutput\n'
+          'Actual:\n$output\n');
+    });
+  });
+}