http2: add tests for cancel event while client is paused reading

PR-URL: https://github.com/nodejs/node/pull/39622
Refs: https://github.com/nodejs/node/pull/39423
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Beth Griggs <bgriggs@redhat.com>

test/parallel/test-http2-cancel-while-client-reading.js

@@ -0,0 +1,36 @@
+'use strict';
+const common = require('../common');
+const fixtures = require('../common/fixtures');
+if (!common.hasCrypto) {
+  common.skip('missing crypto');
+}
+
+const http2 = require('http2');
+const key = fixtures.readKey('agent1-key.pem', 'binary');
+const cert = fixtures.readKey('agent1-cert.pem', 'binary');
+
+const server = http2.createSecureServer({ key, cert });
+
+let client_stream;
+
+server.on('stream', common.mustCall(function(stream) {
+  stream.resume();
+  stream.on('data', function(chunk) {
+    stream.write(chunk);
+    client_stream.pause();
+    client_stream.close(http2.constants.NGHTTP2_CANCEL);
+  });
+}));
+
+server.listen(0, function() {
+  const client = http2.connect(`https://localhost:${server.address().port}`,
+                               { rejectUnauthorized: false }
+  );
+  client_stream = client.request({ ':method': 'POST' });
+  client_stream.on('close', common.mustCall(() => {
+    client.close();
+    server.close();
+  }));
+  client_stream.resume();
+  client_stream.write(Buffer.alloc(1024 * 1024));
+});