Use built-in `AbortController`

[james-pre]

AbortController is available as a built-in on all platforms. readable-stream currently uses the abort-controller dependency. Since AbortController already exists, this dependency can be removed, which decreases the size of readable-stream while increasing supply chain security. Furthermore, native implementations are likely faster.

I'm willing to do a PR for this.

[MattiasBuelens]

AbortController was added in Node 14.17.0. However, readable-stream supports Node 12 and higher (see README). So I'm afraid we can't remove this dependency just yet.

Note that if globalThis.AbortController exists, readable-stream will use it and not load abort-controller:

readable-stream/lib/ours/util.js

Lines 9 to 10 in 88df210

	const AbortSignal = globalThis.AbortSignal || require('abort-controller').AbortSignal
	const AbortController = globalThis.AbortController || require('abort-controller').AbortController

So if you don't need to support Node 12 in your app and can assume that globalThis.AbortController will always exist, you can configure your package manager or bundler to remove that dependency while building.

[james-pre]

If that's the case, a conditional dependency should be used. This would allow abort-controller to not be installed when using a new enough version of Node.