remove unused allowConstCast option

test/codegen_test.dart

 // Copyright (c) 2015, 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.
 
 /// Tests code generation.
 /// Runs Dart Dev Compiler on all input in the `codegen` directory and checks
 /// that the output is what we expected.
 library dev_compiler.test.codegen_test;
 
 import 'dart:io';
@@ skipping 44 matching lines @@
       .where((f) => f is File)
       .map((f) => f.path)
       .where((p) => p.endsWith('.dart') && filePattern.hasMatch(p));
 
   compile(String entryPoint, String sdkPath, {bool checkSdk: false,
       bool serverMode: false, bool sourceMaps: false, String subDir}) {
     // TODO(jmesserly): add a way to specify flags in the test file, so
     // they're more self-contained.
     var runtimeDir = path.join(path.dirname(testDirectory), 'lib', 'runtime');
     var options = new CompilerOptions(
-        allowConstCasts: true,
         outputDir: subDir == null ? actualDir : path.join(actualDir, subDir),
         useColors: false,
         emitSourceMaps: sourceMaps,
         forceCompile: checkSdk,
         checkSdk: checkSdk,
         entryPointFile: entryPoint,
         dartSdkPath: sdkPath,
         runtimeDir: runtimeDir,
         serverMode: serverMode,
         enableHashing: serverMode);
@@ skipping 190 matching lines @@
     print('[AnalysisEngine] error $message $exception');
   }
 
   @override void logError2(String message, Object exception) {
     print('[AnalysisEngine] error $message $exception');
   }
 
   void logInformation(String message, [CaughtException exception]) {}
   void logInformation2(String message, Object exception) {}
 }