Make the `enableSchedulingProfiler` flag dynamic for the profiling build (so marks can be disabled). I think it should be sufficient to do something like:
```js
export const enableSchedulingProfiler =
  __PROFILE__ && dynamicFeatureFlags.enableSchedulingProfiler;
```

Update our User Timing API check to include `clearMeasures` and when we call `mark(name)`, also call `clearMeasures(name)` to avoid clogging the entries buffer. (Apparently this has a significant negative performance impact for Firefox.)
const [didRender, setDidRender] = React.useState(false);
      if (!didRender) {
        setDidRender(true);
      }
      return didRender;
    }
    ReactTestRenderer.unstable_concurrentAct(() => {
      ReactTestRenderer.create(<Example />, {unstable_isConcurrent: true});
    });
    gate(({old}) =>
      old
        ? expect(marks).toContain('--schedule-state-update-1024-Example')
        : expect(marks).toContain('--schedule-state-update-512-Example'),
    );
  });
});