Implement nativePerformanceNow to improve Profiler API results (#27885)
Summary:
When experimenting with React Profiler API (https://reactjs.org/docs/profiler.html), I noticed that durations are integers without a debugger, but they are doubles with higher precision when debugger is attached. After digging into React Profiler code, I found out that it's using `performance.now()` to accumulate execution times of individual units of work. Since this method does not exist in React Native, it falls back to Javascript `Date`, leading to imprecise results.
This PR introduces `global.nativePerformanceNow` function which returns precise native time, and a very basic `performance` polyfill with `now` function.
This will greatly improve React Profiler API results, which is essential for profiling and benchmark tools.
Solves https://github.com/facebook/react-native/issues/27274
## Changelog
[General] [Added] - Implement `nativePerformanceNow` and `performance.now()`
Pull Request resolved: https://github.com/facebook/react-native/pull/27885
Test Plan:
```
const initialTime = global.performance.now();
setTimeout(() => {
const newTime = global.performance.now();
console.warn('duration', newTime - initialTime);
}, 1000);
```
### Android + Hermes
### Android + JSC
### iOS
Reviewed By: ejanzer
Differential Revision: D19888289
Pulled By: rickhanlonii
fbshipit-source-id: ab8152382da9aee9b4b3c76f096e45d40f55da6c
232517a574
