test(react-debug-tools): Improve coverage of currentDispatcher.current setter

[eps1lon]

Summary

Partial fix for #24915

The tests were relying on runtime error messages. These changed between Node 14.x and 16.x. Instead we now throw an error whose message we control.

Seems to me we can make the test pass multiple node versions while also improving the tests by testing that the current dispatcher is actually proxied.

Alternatively we keep the old testing approach and instead of hardcoding the error message we compute it at runtime with

let nullReadUseStateErrorMessage;
try {
  null.useState();
} catch (error) {
  nullReadUseStateErrorMessage = error.message;
}

How did you test this change?

• volta pin node@14.17.0; yarn; yarn test
• volta pin node@16.16.0; yarn; yarn test
• CI

[sizebot]

Comparing: 0220609...74a1306

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	=	133.01 kB	133.01 kB	=	42.65 kB	42.65 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	=	138.23 kB	138.23 kB	=	44.15 kB	44.15 kB
facebook-www/ReactDOM-prod.classic.js	=	468.56 kB	468.56 kB	=	84.30 kB	84.31 kB
facebook-www/ReactDOM-prod.modern.js	=	453.80 kB	453.80 kB	=	82.07 kB	82.07 kB
facebook-www/ReactDOMForked-prod.classic.js	=	468.56 kB	468.56 kB	=	84.30 kB	84.30 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 74a1306

[acdlite]

Makes sense to me!