[test] Fix DevTools regression tests

[eps1lon]

Fixes

IgnoreMe suspended while rendering, but no fallback UI was specified.

-- https://github.com/facebook/react/actions/runs/20886558894/job/60010693969

Regressed in #35456 because in React 17 we can't suspend the root.

It's interesting to test both 17 (because Suspense has a different impl in 17) as well as testing what happens if the root suspends (if the root wouldn't have a dedicated Suspense node, we'd need to change how we handle this case). So we test both React 17 upwards with an explicit root Suspense and React 18 upwards with an implicit one.

Test plan

$ yarn build react-debug-tools react-refresh internal-test-utils
$ ./scripts/ci/download_devtools_regression_build.js 17.0 --replaceBuild
$ node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion 17.0

[hoxyq]

Would it make sense to add another test with the same steps that targets >=18? Because the one right above uses different tree.

You could also add forking inside the test, with something like this?

react/packages/react-devtools-shared/src/__tests__/preprocessData-test.js

Lines 15 to 17 in 5aec1b2

	import {ReactVersion} from '../../../../ReactVersions';
	const ReactVersionTestingAgainst = process.env.REACT_VERSION || ReactVersion;

[eps1lon]

That's the test below. The test above can only work in 18.

I was looking for a pattern to fork assertions on the React version. I'd prefer that to avoid confusion so I'll use the same approach you linked.