set priority on TaskController instead of on postTask/yield (#27295)

## Summary

passing both a signal and a priority to `postTask`/`yield` in chrome
causes memory to spike and potentially causes OOMs. a fix for this has
landed in chrome 118, but we can avoid the issue in earlier versions by
setting priority on just the TaskController instead.

https://bugs.chromium.org/p/chromium/issues/detail?id=1469367

## How did you test this change?
```
yarn test SchedulerPostTask
```

packages/scheduler/src/__tests__/SchedulerPostTask-test.js

@@ -83,7 +83,8 @@ describe('SchedulerPostTask', () => {
     const scheduler = {};
     global.scheduler = scheduler;
 
-    scheduler.postTask = function (callback, {priority, signal}) {
+    scheduler.postTask = function (callback, {signal}) {
+      const {priority} = signal;
       const id = idCounter++;
       log(
         `Post Task ${id} [${priority === undefined ? '<default>' : priority}]`,
@@ -94,7 +95,8 @@ describe('SchedulerPostTask', () => {
       });
     };
 
-    scheduler.yield = function ({priority, signal}) {
+    scheduler.yield = function ({signal}) {
+      const {priority} = signal;
       const id = idCounter++;
       log(`Yield ${id} [${priority === undefined ? '<default>' : priority}]`);
       const controller = signal._controller;
@@ -111,8 +113,8 @@ describe('SchedulerPostTask', () => {
     };
 
     global.TaskController = class TaskController {
-      constructor() {
-        this.signal = {_controller: this};
+      constructor({priority}) {
+        this.signal = {_controller: this, priority};
       }
       abort() {
         const task = taskQueue.get(this);

packages/scheduler/src/forks/SchedulerPostTask.js

@@ -10,7 +10,7 @@
 import type {PriorityLevel} from '../SchedulerPriorities';
 
 declare class TaskController {
-  constructor(priority?: string): TaskController;
+  constructor(options?: {priority?: string}): TaskController;
   signal: mixed;
   abort(): void;
 }
@@ -95,9 +95,8 @@ export function unstable_scheduleCallback<T>(
       break;
   }
 
-  const controller = new TaskController();
+  const controller = new TaskController({priority: postTaskPriority});
   const postTaskOptions = {
-    priority: postTaskPriority,
     delay: typeof options === 'object' && options !== null ? options.delay : 0,
     signal: controller.signal,
   };
@@ -130,9 +129,10 @@ function runTask<T>(
     if (typeof result === 'function') {
       // Assume this is a continuation
       const continuation: SchedulerCallback<T> = (result: any);
-      const continuationController = new TaskController();
-      const continuationOptions = {
+      const continuationController = new TaskController({
         priority: postTaskPriority,
+      });
+      const continuationOptions = {
         signal: continuationController.signal,
       };
       // Update the original callback node's controller, since even though we're