[dart:io][windows] Make unicode characters display correctly.

runtime/bin/file_unsupported.cc

Index: runtime/bin/file_unsupported.cc
diff --git a/runtime/bin/file_unsupported.cc b/runtime/bin/file_unsupported.cc
index 9196c22b0710fc205359fcd8e64093997a443a44..e64524d811efbd8ee35baa35a482caba10051391 100644
--- a/runtime/bin/file_unsupported.cc
+++ b/runtime/bin/file_unsupported.cc
@@ -24,6 +24,12 @@ void FUNCTION_NAME(File_SetPointer)(Dart_NativeArguments args) {
 }
 
 
+void FUNCTION_NAME(File_SetTranslation)(Dart_NativeArguments args) {
+  Dart_ThrowException(
+      DartUtils::NewInternalError("File is not supported on this platform"));
+}
+
+
 void FUNCTION_NAME(File_Open)(Dart_NativeArguments args) {
   Dart_ThrowException(
       DartUtils::NewInternalError("File is not supported on this platform"));