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.)
if (supportsUserTiming) {
      performance.mark('--layout-effects-stop');
    }
  }
}
export function markPassiveEffectsStarted(lanes: Lanes): void {
  if (enableSchedulingProfiler) {
    if (supportsUserTiming) {
      performance.mark(`--passive-effects-start-${formatLanes(lanes)}`);
    }
  }
}
export function markPassiveEffectsStopped(): void {
  if (enableSchedulingProfiler) {
    if (supportsUserTiming) {
      performance.mark('--passive-effects-stop');
    }
  }
}
export function markRenderStarted(lanes: Lanes): void {
  if (enableSchedulingProfiler) {
    if (supportsUserTiming) {
      performance.mark(`--render-start-${formatLanes(lanes)}`);
    }
  }
}
export function markRenderYielded(): void {
  if (enableSchedulingProfiler) {
    if (supportsUserTiming) {
      performance.mark('--render-yield');