stream: keep webstreams controller state fast

Controller instances declared only [kType] and set [kState] later in the
setup function, so each construction took a shape transition when setup
added the slot. Declaring [kState] keeps the slot in the initial map and
makes the setup assignment an in-place store. Applied to the readable
default, readable byte, writable, and transform controllers so all four
share the same instance shape.

Assisted-by: pi
Signed-off-by: Matteo Collina <hello@matteocollina.com>

Author: mcollina

lib/internal/webstreams/readablestream.js

@@ -1140,6 +1140,7 @@ ObjectDefineProperties(ReadableStreamBYOBReader.prototype, {
 
 class ReadableStreamDefaultController {
   [kType] = 'ReadableStreamDefaultController';
+  [kState];
 
   constructor(skipThrowSymbol = undefined) {
     if (skipThrowSymbol !== kSkipThrow) {
@@ -1202,6 +1203,7 @@ ObjectDefineProperties(ReadableStreamDefaultController.prototype, {
 
 class ReadableByteStreamController {
   [kType] = 'ReadableByteStreamController';
+  [kState];
 
   constructor(skipThrowSymbol = undefined) {
     if (skipThrowSymbol !== kSkipThrow) {

lib/internal/webstreams/transformstream.js

@@ -303,6 +303,7 @@ TransferredTransformStream.prototype[kDeserialize] = () => {};
 
 class TransformStreamDefaultController {
   [kType] = 'TransformStreamDefaultController';
+  [kState];
 
   constructor(skipThrowSymbol = undefined) {
     if (skipThrowSymbol !== kSkipThrow) {

lib/internal/webstreams/writablestream.js

@@ -502,6 +502,7 @@ ObjectDefineProperties(WritableStreamDefaultWriter.prototype, {
 
 class WritableStreamDefaultController {
   [kType] = 'WritableStreamDefaultController';
+  [kState];
 
   constructor(skipThrowSymbol = undefined) {
     if (skipThrowSymbol !== kSkipThrow) {