[dart:io][windows] Use WriteFile instead of _write

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 e64524d811efbd8ee35baa35a482caba10051391..9196c22b0710fc205359fcd8e64093997a443a44 100644
--- a/runtime/bin/file_unsupported.cc
+++ b/runtime/bin/file_unsupported.cc
@@ -24,12 +24,6 @@ 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"));