I've observed that when React's profiling mode is enabled, updating the profiling fields [here](https://github.com/facebook/react/blob/1d25aa5787d4e19704c049c3cfa985d3b5190e0d/packages/react-reconciler/src/ReactProfilerTimer.js#L46) and [here](https://github.com/facebook/react/blob/1d25aa5787d4e19704c049c3cfa985d3b5190e0d/packages/react-reconciler/src/ReactProfilerTimer.js#L69-L71) during the _render_ phase seems to cause a significant deopt in [`getHostSibling`](https://github.com/facebook/react/blob/1d25aa5787d4e19704c049c3cfa985d3b5190e0d/packages/react-reconciler/src/ReactFiberCommitWork.js#L858-L898) during the _commit_ phase for Chrome only. (Neither Safari nor Firefox seem to be affected by this.)

I have created a repro case with inline annotations here:
https://github.com/bvaughn/react-profiling-v8-deopt-repro#about-this-repro-case

(Note that the above repo is private. Please tag me here if you need access.)
REACT_LAZY_TYPE,
} from 'shared/ReactSymbols';
let hasBadMapPolyfill;
if (__DEV__) {
  hasBadMapPolyfill = false;
  try {
    const nonExtensibleObject = Object.preventExtensions({});
    const testMap = new Map([[nonExtensibleObject, null]]);
    const testSet = new Set([nonExtensibleObject]);
    
    
    
    testMap.set(0, 0);
    testSet.add(0);
  } catch (e) {
    
    hasBadMapPolyfill = true;
  }
}
export type Fiber = {|
  
  
  
  
  
  
  
  
  
  tag: WorkTag,