Align React Native OSS/Test Feature Flags (#28677)

## Summary

Makes a few changes to align React Native feature flags for open source
and internal test renderer configurations.

* Enable `enableSchedulingProfiler` for profiling builds.
* Align `ReactFeatureFlags.test-renderer.native.js` (with
`ReactFeatureFlags.native-fb.js`).
  * Enable `enableUseMemoCacheHook`.
  * Enable `enableFizzExternalRuntime`.
  * Disable `alwaysThrottleRetries`.

## How did you test this change?

Ran the following successfully:

```
$ yarn test
$ yarn flow native
$ yarn flow fabric
```

DiffTrain build for commit 425f72b.

Author: yungsters