next.js

a64f6b07 - test: replace duplicate test utils to next instance (#73624)

test: replace duplicate test utils to next instance (#73624) This PR replaces: - `renderViaHTTP -> next.render` - `cheerio.load -> next.render$` - ~~`process.env.TURBOPACK` -> `isTurbopack`~~ (left as `process.env.IS_TURBOPACK_TEST`)