Summary:

Changelog: [internal]

Adds tinybench 3.1.0 (which has support for sync execution) and defined Flow types for the package.

Reviewed By: dmytrorykun

Differential Revision: D66698545

Summary:

Changelog: [internal]

Implements a basic API to run benchmarks with Fantom (using `tinybench` under the hood):

```
import {benchmark} from 'react-native/fantom';

benchmark
  .suite('Suite name', {
    // options
  })
  .add(
    'Test name',
    () => {
      // code to benchmark
    },
    {
      beforeAll: () => {},
      beforeEach: () => {},
      afterEach: () => {},
      afterAll: () => {},
    },
  )
  .verify(results => {
    // check results and throw an error if the expectations fail
  });
```

Features:
* Print benchmark results in the console as a table.
* It opts into optimized builds automatically
* Verifies that optimized build is used (unless manually opting out of the check via `disableOptimizedBuildCheck`).
* Supports verification of results (making expectations and making the test fail if the benchmark doesn't meet some expectations).

Reviewed By: rshest

Differential Revision: D66926183

…n functions in CI (facebook#48451)

Summary:

Changelog: [internal]

Modifies the execution of benchmarks in CI to run benchmarks in test mode when they don't define a `verify` method.

If a benchmark uses `verify`, the test is meant to make sure that the benchmark doesn't regress in CI. If it doesn't, then running the benchmark on CI doesn't provide much value. In that case, we run a single iteration of each test case just to make sure things don't break over time.

Reviewed By: rshest

Differential Revision: D67637754

Summary:

Changelog: [internal]

This implements a basic benchmark to compare `ReactFabricHostComponent` and `ReactNativeElement` (legacy and DOM implementations for native component instances).

Reviewed By: rshest

Differential Revision: D66698546