src: clean up StreamPipe in destructor

In the presence of Workers, it is not safe to assume that
`StreamPipe::Unpipe()` has been called at the time when the object
is destroyed.

Instead, clean up when the destructor is called.

PR-URL: #26256
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

src/stream_pipe.cc

@@ -42,7 +42,7 @@ StreamPipe::StreamPipe(StreamBase* source,
 }
 
 StreamPipe::~StreamPipe() {
-  CHECK(is_closed_);
+  Unpipe();
 }
 
 StreamBase* StreamPipe::source() {

test/parallel/test-worker-terminate-http2-respond-with-file.js

@@ -0,0 +1,39 @@
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const assert = require('assert');
+const http2 = require('http2');
+const makeDuplexPair = require('../common/duplexpair');
+const { Worker, isMainThread } = require('worker_threads');
+
+// This is a variant of test-http2-generic-streams-sendfile for checking
+// that Workers can be terminated during a .respondWithFile() operation.
+
+if (isMainThread) {
+  return new Worker(__filename);
+}
+
+{
+  const server = http2.createServer();
+  server.on('stream', common.mustCall((stream, headers) => {
+    stream.respondWithFile(process.execPath);  // Use a large-ish file.
+  }));
+
+  const { clientSide, serverSide } = makeDuplexPair();
+  server.emit('connection', serverSide);
+
+  const client = http2.connect('http://localhost:80', {
+    createConnection: common.mustCall(() => clientSide)
+  });
+
+  const req = client.request();
+
+  req.on('response', common.mustCall((headers) => {
+    assert.strictEqual(headers[':status'], 200);
+  }));
+
+  req.on('data', common.mustCall(process.exit));
+  req.on('end', common.mustNotCall());
+  req.end();
+}