[webtranport] Update streamErrorCode to 32-bit long

The latest version of WebTransport protocol uses 32-bit unsigned
integer for streamErrorCode [1, 2, 3].

[1] ietf-wg-webtrans/draft-ietf-webtrans-http3#115
[2] w3c/webtransport#509
[3] w3c/webtransport#527

Bug: 1465282
Change-Id: I3a3cf9936e09ea2a0b6bb01df18ffd1d9fb287bc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4693162
Reviewed-by: Adam Rice <ricea@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1172268}

webtransport/streams-close.https.any.js

@@ -204,7 +204,7 @@ promise_test(async t => {
 }, 'Abort unidirectional stream with default error code');
 
 promise_test(async t => {
-  const WT_CODE = 240;
+  const WT_CODE = 0;
   const HTTP_CODE = webtransport_code_to_http_code(WT_CODE);
   const wt = new WebTransport(
     webtransport_url(`abort-stream-from-server.py?code=${HTTP_CODE}`));
@@ -229,7 +229,7 @@ promise_test(async t => {
 }, 'STOP_SENDING coming from server');
 
 promise_test(async t => {
-  const WT_CODE = 127;
+  const WT_CODE = 0xffffffff;
   const HTTP_CODE = webtransport_code_to_http_code(WT_CODE);
   const wt = new WebTransport(
     webtransport_url(`abort-stream-from-server.py?code=${HTTP_CODE}`));