Fix assertion when writing to a closed writable stream

[domenic]

Closes #1341. /cc @daeyeon

• At least two implementers are interested (and none opposed):
  • Matches Chromium
  • Matches Firefox
• Tests are written and can be reviewed and commented upon at:
  • Test write()ing to a closed writable stream web-platform-tests/wpt#51819
• Implementation bugs are filed:
  • Chromium: N/A
  • Gecko: N/A
  • WebKit: https://bugs.webkit.org/show_bug.cgi?id=283739
  • Deno: Streams: writableStreamDefaultControllerGetChunkSize undefined strategy case slightly broken denoland/deno#27102
  • Node.js: Fixed already by stream: fix sizeAlgorithm validation in WritableStream nodejs/node#57280
• MDN issue is filed: N/A
• The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

---

Preview | Diff

[annevk]

(Trusting the WPT submodule change.)