Remove conditional require()s from SSR

[MrDoomBringer]

Gets rid of some conditional require()s from getDataFromTree and renderToStringWithData, which won't get bundled properly by webpack.

Checklist:

See #9952 for more information

• If this PR is a new feature, please reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests

[MrDoomBringer]

As a side note, if we did still want to run this with JSDOM, we can manually add TextEncoder to the jest environment in the config/jest/setup.ts file like so:

if (typeof global.TextEncoder === 'undefined') {
    const { TextEncoder, TextDecoder } = require('util');
    global.TextEncoder = TextEncoder;
    global.TextDecoder = TextDecoder;
}

Given the scope of this it seemed unnecessary to me, but let me know if you think otherwise.

[hwillson]

Just dropping this here: apollographql/react-apollo#2627 - it shows that one of the original motivations for the conditional require was to work around issues with React Native.

[benjamn]

Looking at apollographql/react-apollo#2627 (thanks @hwillson), I see the "react-dom/server": false trick never made it from the old react-apollo/package.json to the current @apollo/client/package.json (now that React Apollo has been fully merged into the @apollo/client/react package).

@MrDoomBringer I wonder if that "react-dom/server": false in package.json technique might be enough to prevent React Native from mistakenly trying to bundle react-dom/server?

[MrDoomBringer]

@benjamn Thanks for the callout! I was actually just looking at the commit that we lost it in here - apollographql/react-apollo@29a4536. Will take a look.