fix strong mode messages in pkg/dev_compiler

pkg/dev_compiler/test/codegen_test.dart

Index: pkg/dev_compiler/test/codegen_test.dart
diff --git a/pkg/dev_compiler/test/codegen_test.dart b/pkg/dev_compiler/test/codegen_test.dart
index 0d1dbd922560e5b309aa44da0b2ca716b143311e..7b3577f7aee65e8ef563704b31ff6a39c9eb10f7 100644
--- a/pkg/dev_compiler/test/codegen_test.dart
+++ b/pkg/dev_compiler/test/codegen_test.dart
@@ -26,11 +26,7 @@ import 'package:dev_compiler/src/analyzer/context.dart' show AnalyzerOptions;
 import 'package:dev_compiler/src/compiler/compiler.dart'
     show BuildUnit, CompilerOptions, JSModuleFile, ModuleCompiler;
 import 'package:dev_compiler/src/compiler/module_builder.dart'
-    show
-        ModuleFormat,
-        addModuleFormatOptions,
-        parseModuleFormatOption,
-        pathToJSIdentifier;
+    show ModuleFormat, addModuleFormatOptions, parseModuleFormatOption;
 import 'package:path/path.dart' as path;
 import 'package:test/test.dart' show expect, isFalse, isTrue, test;