Remove the checker and corresponding dead code

test/codegen_test.dart

Index: test/codegen_test.dart
diff --git a/test/codegen_test.dart b/test/codegen_test.dart
index dac69944d4637a86e388b74d642fcd37671ccba7..66e41c82ffaa2ef1f80afd2cb6a22e302e4c58fe 100644
--- a/test/codegen_test.dart
+++ b/test/codegen_test.dart
@@ -17,7 +17,6 @@ import 'package:path/path.dart' as path;
 import 'package:test/test.dart';
 
 import 'package:dev_compiler/devc.dart';
-import 'package:dev_compiler/strong_mode.dart';
 import 'package:dev_compiler/src/compiler.dart' show defaultRuntimeFiles;
 import 'package:dev_compiler/src/options.dart';
 
@@ -184,7 +183,6 @@ $compilerMessages''';
 
       test('devc dart:core', () {
         var testSdkContext = createAnalysisContextWithSources(
-            new StrongModeOptions(),
             new SourceResolverOptions(
                 dartSdkPath:
                     path.join(testDirectory, '..', 'tool', 'generated_sdk')));