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

runtime/bin/file_macos.cc

Index: runtime/bin/file_macos.cc
diff --git a/runtime/bin/file_macos.cc b/runtime/bin/file_macos.cc
index 32509600a66b0e8ebe368a571201ff82037d3147..9f09b7932a21d9b74fae2a63702dd10afefab901 100644
--- a/runtime/bin/file_macos.cc
+++ b/runtime/bin/file_macos.cc
@@ -154,11 +154,6 @@ bool File::SetPosition(int64_t position) {
 }
 
 
-// There is no difference between binary and text translation modes on this
-// platform, so this operation is a no-op.
-void File::SetTranslation(DartFileTranslation translation) {}
-
-
 bool File::Truncate(int64_t length) {
   ASSERT(handle_->fd() >= 0);
   return TEMP_FAILURE_RETRY(ftruncate(handle_->fd(), length)) != -1;