### Describe what you were doing when the bug occurred:
1. I did profiling on a list, that gets updated on each pagination api call.
2. Once the profiling was done, I moved around in the Profiler to view the Flamegraph
3. Moving to second capture, the Profiler crashed.


**DevTools version**: 4.6.0-6cceaeb67

```
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    in n
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```
pendingOperations.length = 0;
    }, 1000);
  }
  function reevaluateErrorsAndWarnings() {
    fibersWithChangedErrorOrWarningCounts.clear();
    fiberToErrorsMap.forEach((countMap, fiberID) => {
      fibersWithChangedErrorOrWarningCounts.add(fiberID);
    });
    fiberToWarningsMap.forEach((countMap, fiberID) => {
      fibersWithChangedErrorOrWarningCounts.add(fiberID);
    });
    recordPendingErrorsAndWarnings();
  }
  function recordPendingErrorsAndWarnings() {
    clearPendingErrorsAndWarningsAfterDelay();
    fibersWithChangedErrorOrWarningCounts.forEach(fiberID => {
      const fiber = idToFiberMap.get(fiberID);
      if (fiber != null) {
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        if (isFiberMountedImpl(fiber) !== MOUNTED) {
          fiberToIDMap.delete(fiber);
          idToFiberMap.delete(fiberID);
          primaryFibers.delete(fiber);
          return;
        }
        let errorCount = 0;
        let warningCount = 0;
        if (!shouldFilterFiber(fiber)) {