Make try/catch/finally work with Kernel code and some refactoring.

tests/compiler/dart2js/kernel/try_catch_test.dart

+// Copyright (c) 2016, 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.
+
+import 'package:test/test.dart';
+
+import 'helper.dart' show check;
+
+main() {
+  test('try catch', () {
+    String code = '''
+main() {
+  try {
+    print('hi');
+  } catch (e, s) {
+    print(e);
+    print(s);
+    print('bye');
+  }
+}''';
+    return check(code);
+  });
+
+  test('try omit catch', () {
+    String code = '''
+main() {
+  try {
+    print('hi');
+  } on ArgumentError {
+    print('howdy');
+  }
+}''';
+    return check(code);
+  });
+
+  test('try finally', () {
+    String code = '''
+main() {
+  try {
+    print('hi');
+  } finally {
+    print('bye');
+  }
+}''';
+    return check(code);
+  });
+
+  test('try catch finally', () {
+    String code = '''
+main() {
+  try {
+    print('hi');
+  } catch(e) {
+    print('howdy');
+  } finally {
+    print('bye');
+  }
+}''';
+    return check(code);
+  });
+
+  test('try multi catch', () {
+    String code = '''
+main() {
+  try {
+    print('hi');
+  } on String catch(e) {
+    print('hola');
+  } on int catch(e) {
+    print('halo');
+  } catch (e) {
+    print('howdy');
+  }
+}''';
+    return check(code);
+  });
+
+  test('try multi-catch finally', () {
+    String code = '''
+main() {
+  try {
+    print('hi');
+  } on String catch(e) {
+    print('hola');
+  } on int catch(e) {
+    print('halo');
+  } catch (e) {
+    print('howdy');
+  } finally {
+    print('bye');
+  }
+}''';
+    return check(code);
+  });
+}
+