Add option --compile-sdk to fasta compile and run.

pkg/front_end/test/subpackage_relationships_test.dart

 // Copyright (c) 2017, 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 'dart:async';
 import 'dart:io';
 
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/dependency_grapher.dart';
 import 'package:path/path.dart' as pathos;
@@ skipping 72 matching lines @@
     'lib/src/fasta/util',
   ]),
   'lib/src/fasta/source': new SubpackageRules(allowedDependencies: [
     'lib/src/fasta',
     'lib/src/fasta/analyzer',
     'lib/src/fasta/builder',
     'lib/src/fasta/dill',
     'lib/src/fasta/kernel',
     'lib/src/fasta/parser',
     'lib/src/fasta/scanner',
+    'lib/src/fasta/util',
   ]),
   'lib/src/fasta/testing':
       new SubpackageRules(mayImportAnalyzer: true, allowedDependencies: [
     'lib/src/fasta',
     'lib/src/fasta/dill',
     'lib/src/fasta/kernel',
   ]),
   'lib/src/fasta/util': new SubpackageRules(),
   'lib/src/scanner': new SubpackageRules(allowedDependencies: [
     'lib/src/base',
@@ skipping 123 matching lines @@
       problem('Uri $src is inside package:front_end but is not in any known '
           'subpackage');
     } else if (!subpackageRules[subpackage].allowSubdirs &&
         pathWithinSubpackage.contains('/')) {
       problem('Uri $src is in a subfolder of $subpackage, but that '
           'subpackage does not allow dart files in subdirectories.');
     }
     return subpackage;
   }
 }