test: make test-v8-serdes work without stdin

If `stdin` was closed or referred to a file, this didn't work,
because it was accessed via file descriptor.

Instead, use another generic native object.

cherry-picked from ayojs/ayo#63

Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-v8-serdes.js

@@ -20,6 +20,8 @@ const objects = [
  circular
 ];
 
+const hostObject = new (process.binding('js_stream').JSStream)();
+
 const serializerTypeError =
  /^TypeError: Class constructor Serializer cannot be invoked without 'new'$/;
 const deserializerTypeError =
@@ -63,8 +65,8 @@ const deserializerTypeError =
 {
  const ser = new v8.DefaultSerializer();
  ser._writeHostObject = common.mustCall((object) => {
- assert.strictEqual(object, process.stdin._handle);
- const buf = Buffer.from('stdin');
+ assert.strictEqual(object, hostObject);
+ const buf = Buffer.from('hostObjectTag');
 
  ser.writeUint32(buf.length);
  ser.writeRawBytes(buf);
@@ -74,23 +76,23 @@ const deserializerTypeError =
  });
 
  ser.writeHeader();
- ser.writeValue({ val: process.stdin._handle });
+ ser.writeValue({ val: hostObject });
 
  const des = new v8.DefaultDeserializer(ser.releaseBuffer());
  des._readHostObject = common.mustCall(() => {
  const length = des.readUint32();
  const buf = des.readRawBytes(length);
 
- assert.strictEqual(buf.toString(), 'stdin');
+ assert.strictEqual(buf.toString(), 'hostObjectTag');
 
  assert.deepStrictEqual(des.readUint64(), [1, 2]);
  assert.strictEqual(des.readDouble(), -0.25);
- return process.stdin._handle;
+ return hostObject;
  });
 
  des.readHeader();
 
- assert.strictEqual(des.readValue().val, process.stdin._handle);
+ assert.strictEqual(des.readValue().val, hostObject);
 }
 
 {
@@ -101,12 +103,12 @@ const deserializerTypeError =
 
  ser.writeHeader();
  assert.throws(() => {
- ser.writeValue({ val: process.stdin._handle });
+ ser.writeValue({ val: hostObject });
  }, /foobar/);
 }
 
 {
- assert.throws(() => v8.serialize(process.stdin._handle),
+ assert.throws(() => v8.serialize(hostObject),
  /^Error: Unknown host object type: \[object .*\]$/);
 }