chore(csv): use TextDecoderStream() in test (denoland#3801)

csv/csv_parse_stream_test.ts

@@ -342,27 +342,14 @@ x,,,
  },
 });
 
-// Work around resource leak error with TextDecoderStream:
-// https://github.com/denoland/deno/issues/13142
-export const MyTextDecoderStream = () => {
- const textDecoder = new TextDecoder();
- return new TransformStream({
- transform(chunk: Uint8Array, controller: TransformStreamDefaultController) {
- controller.enqueue(textDecoder.decode(chunk));
- },
- flush(controller: TransformStreamDefaultController) {
- controller.enqueue(textDecoder.decode());
- },
- });
-};
-
 Deno.test({
  name:
  "[csv/csv_parse_stream] cancel CsvParseStream during iteration does not leak file",
  permissions: { read: [testdataDir] },
  fn: async () => {
  const file = await Deno.open(join(testdataDir, "large.csv"));
- const readable = file.readable.pipeThrough(MyTextDecoderStream())
+ const readable = file.readable
+ .pipeThrough(new TextDecoderStream())
  .pipeThrough(new CsvParseStream());
  for await (const _record of readable) {
  break;