Fizz: Prevent UnhandledPromiseRejectionWarning if renderToReadableStream throws

[eps1lon]

Summary

I noticed a UnhandledPromiseRejectionWarning when running tests (e.g. https://app.circleci.com/pipelines/github/facebook/react/24649/workflows/5b1b67a2-eb4b-4e7e-9dd8-d531328eff6e/jobs/448950/parallel-runs/16).
It seems to me that stream.allReady is not accessible when the shell errors (i.e. renderToReadableStream throws) which means stream.allReady will be left rejected and unhandled.

How did you test this change?

• yarn test ReactDOMFizzServerBrowser logs no UnhandledPromiseRejectionWarning
• ReactDOMFizzServerBrowser logs no UnhandledPromiseRejectionWarning in CI: https://app.circleci.com/pipelines/github/facebook/react/24655/workflows/ad4851cf-0530-4a69-8c36-e7a9bcaf7daa/jobs/449075/parallel-runs/14
• CI

Follow-up?

• fail tests if rejected promises are not handled?

[sizebot]

Comparing: 14c2be8...528e2f4

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.min.js	=	131.46 kB	131.46 kB	=	42.05 kB	42.06 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	=	136.12 kB	136.12 kB	=	43.41 kB	43.41 kB
facebook-www/ReactDOM-prod.classic.js	=	435.09 kB	435.09 kB	=	79.61 kB	79.61 kB
facebook-www/ReactDOM-prod.modern.js	=	421.59 kB	421.59 kB	=	77.60 kB	77.60 kB
facebook-www/ReactDOMForked-prod.classic.js	=	435.09 kB	435.09 kB	=	79.62 kB	79.62 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

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