## Summary
Should unblock https://github.com/facebook/react/pull/25970
If the callback for `toWarnDev` was `async` and threw, we didn't
ultimately reject the await Promise from the matcher. This resulted in
tests failing even though the failure was expected due to a test gate.
## How did you test this change?
- [x] tested in https://github.com/facebook/react/pull/25970 with `yarn
test --r=stable --env=development
packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js --watch`
- [x] `yarn test`
- [x] CI
4f8ffec453