test: add regression test for http2 fd leak

Verifies that the file descriptor is closed when an error occurs during
header validation in respondWithFile.

Refs: 5c4dd6b

Author: Han5991

test/parallel/test-http2-respond-file-fd-leak.js

@@ -0,0 +1,51 @@
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const fixtures = require('../common/fixtures');
+const assert = require('assert');
+const http2 = require('http2');
+const fs = require('fs');
+
+const fname = fixtures.path('elipses.txt');
+
+const server = http2.createServer();
+
+server.on('stream', common.mustCall((stream) => {
+  const originalClose = fs.close;
+  let fdClosed = false;
+
+  fs.close = common.mustCall(function(fd, cb) {
+    fdClosed = true;
+    return originalClose.apply(this, arguments);
+  });
+
+  const headers = {
+    ':method': 'GET',
+    'content-type': 'text/plain'
+  };
+
+  stream.respondWithFile(fname, headers);
+
+  stream.on('error', common.mustCall((err) => {
+    assert.strictEqual(err.code, 'ERR_HTTP2_INVALID_PSEUDOHEADER');
+  }));
+
+  stream.on('close', common.mustCall(() => {
+    fs.close = originalClose;
+    assert.strictEqual(fdClosed, true);
+  }));
+}));
+
+server.listen(0, common.mustCall(() => {
+  const client = http2.connect(`http://localhost:${server.address().port}`);
+  const req = client.request();
+
+  req.on('close', common.mustCall(() => {
+    client.close();
+    server.close();
+  }));
+
+  req.on('error', common.mustCall());
+  req.end();
+}));