Add benchmark for structuredClone (#51249)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/51249

Changelog: [internal]

This adds a basic benchmark for `structuredClone`, so we can optimize it in the following diff.

Baseline:

| (index) | Task name                | Latency average (ns) | Latency median (ns) | Throughput average (ops/s) | Throughput median (ops/s) | Samples |
| ------- | ------------------------ | -------------------- | ------------------- | -------------------------- | ------------------------- | ------- |
| 0       | 'clone a string'         | '955.81 ± 1.45%'     | '902.00'            | '1095925 ± 0.01%'          | '1108647'                 | 1046239 |
| 1       | 'clone a basic array'    | '7684.79 ± 0.76%'    | '7542.00'           | '131980 ± 0.02%'           | '132591'                  | 130128  |
| 2       | 'clone a basic object'   | '6286.35 ± 0.53%'    | '6179.00'           | '161179 ± 0.02%'           | '161838'                  | 159075  |
| 3       | 'clone a complex object' | '22446.96 ± 0.32%'   | '22223.00'          | '44819 ± 0.03%'            | '44998'                   | 44550   |

Reviewed By: hoxyq

Differential Revision: D71407319

fbshipit-source-id: ee1c89d6ba3fd2484b2f4115cc58dc4b08e04fa7

packages/react-native/src/private/webapis/structuredClone/__tests__/structuredClone-benchmark-itest.js

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ * @oncall react_native
+ */
+
+import '@react-native/fantom/src/setUpDefaultReactNativeEnvironment';
+
+import * as Fantom from '@react-native/fantom';
+import structuredClone from 'react-native/src/private/webapis/structuredClone/structuredClone';
+
+const basicArray = [1, 2, 3];
+const basicObject = {a: 1, b: 2, c: 3};
+const complexObject = {
+  a: 1,
+  b: 'foo',
+  c: false,
+  d: undefined,
+  e: {
+    f: {
+      g: [1, 'foo', 'bar'],
+    },
+  },
+};
+
+Fantom.unstable_benchmark
+  .suite('structuredClone')
+  .test('clone a string', () => {
+    structuredClone('hello world');
+  })
+  .test('clone a basic array', () => {
+    structuredClone(basicArray);
+  })
+  .test('clone a basic object', () => {
+    structuredClone(basicObject);
+  })
+  .test('clone a complex object', () => {
+    structuredClone(complexObject);
+  });