### Website or app

https://codesandbox.io/s/react-playground-forked-j4niq

### Repro steps

Emoji seem supported but produce strange symbole

![image](https://user-images.githubusercontent.com/24865815/133793744-55a55582-90ad-425f-8a40-4c061a3c1d80.png)

To test emoji on Window Os, use `[win]+[.]` 🟩


### How often does this bug happen?

Every time

### DevTools package (automated)

_No response_

### DevTools version (automated)

_No response_

### Error message (automated)

_No response_

### Error call stack (automated)

_No response_

### Error component stack (automated)

_No response_

### GitHub query string (automated)

_No response_
if (fiber != null) {
        fibersWithChangedErrorOrWarningCounts.add(fiber);
      }
    });
    recordPendingErrorsAndWarnings();
  }
  function mergeMapsAndGetCountHelper(
    fiber: Fiber,
    fiberID: number,
    pendingFiberToMessageCountMap: Map<Fiber, Map<string, number>>,
    fiberIDToMessageCountMap: Map<number, Map<string, number>>,
  ): number {
    let newCount = 0;
    let messageCountMap = fiberIDToMessageCountMap.get(fiberID);
    const pendingMessageCountMap = pendingFiberToMessageCountMap.get(fiber);
    if (pendingMessageCountMap != null) {
      if (messageCountMap == null) {
        messageCountMap = pendingMessageCountMap;
        fiberIDToMessageCountMap.set(fiberID, pendingMessageCountMap);
      } else {
         T
        const refinedMessageCountMap = ((messageCountMap: any): Map<
          string,
          number,
        >);
        pendingMessageCountMap.forEach((pendingCount, message) => {
          const previousCount = refinedMessageCountMap.get(message) || 0;
          refinedMessageCountMap.set(message, previousCount + pendingCount);
        });
      }