Bug 1595736 [wpt PR 20205] - Verify piping disturbs stream synchronously, a=testonly

Automatic update from web-platform-tests
Verify piping disturbs stream synchronously (#20205)

whatwg/streams#1022 changes pipeTo and
pipeThrough to always set the [[disturbed]] slot of the Response's body
to true synchronously.

This test verifies that behaviour.
--

wpt-commits: 760485a4f652813d1f195ee28042c391cf2fdc02
wpt-pr: 20205

UltraBlame original commit: fcba8dc0552eb96c10b6997d7313972e5177ac93

Author: marco-c

testing/web-platform/tests/fetch/api/response/response-stream-disturbed-by-pipe.any.js

@@ -0,0 +1,15 @@
+test(() => {
+  const r = new Response(new ReadableStream());
+  
+  r.body.pipeTo(new WritableStream({}, {highWaterMark: 0}));
+  assert_true(r.bodyUsed, 'bodyUsed should be true');
+}, 'using pipeTo on Response body should disturb it synchronously');
+
+test(() => {
+  const r = new Response(new ReadableStream());
+  r.body.pipeThrough({
+    writable: new WritableStream({}, {highWaterMark: 0}),
+    readable: new ReadableStream()
+  });
+  assert_true(r.bodyUsed, 'bodyUsed should be true');
+}, 'using pipeThrough on Response body should disturb it synchronously');