chore: remove old traces of next/data experiment

[Timer]

This PR removes some left over traces of the next/data experiment, as it has been superseded by RSC.

[ijjk]

Stats from current PR

Default Server Mode (Increase detected ⚠️)

General Overall decrease ✓

	vercel/next.js canary	Timer/next.js remove/next-data	Change
buildDuration	11.1s	10.8s	-336ms
nodeModulesSize	80.6 MB	80.6 MB	-7.82 kB

Page Load Tests Overall increase ✓

	vercel/next.js canary	Timer/next.js remove/next-data	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.304	2.284	-0.02
/ avg req/sec	1085.26	1094.77	+9.51
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.643	1.576	-0.07
/error-in-render avg req/sec	1521.26	1585.92	+64.66

Client Bundles (main, webpack, commons)

	vercel/next.js canary	Timer/next.js remove/next-data	Change
677f882d2ed8..42af.js gzip	13 kB	13 kB	✓
framework.HASH.js gzip	39 kB	39 kB	✓
main-243368f..7063.js gzip	6.59 kB	6.59 kB	✓
webpack-50be..df5b.js gzip	751 B	751 B	✓
Overall change	59.3 kB	59.3 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	Timer/next.js remove/next-data	Change
polyfills-81..14d7.js gzip	31.2 kB	31.2 kB	✓
Overall change	31.2 kB	31.2 kB	✓

Client Pages

	vercel/next.js canary	Timer/next.js remove/next-data	Change
_app-b6fc6bc..222c.js gzip	1.28 kB	1.28 kB	✓
_error-cfcb6..fe1c.js gzip	3.44 kB	3.44 kB	✓
hooks-010c20..8411.js gzip	887 B	887 B	✓
index-bbee2f..528b.js gzip	227 B	227 B	✓
link-705099c..c35d.js gzip	1.64 kB	1.64 kB	✓
routerDirect..bf84.js gzip	303 B	303 B	✓
withRouter-a..5826.js gzip	302 B	302 B	✓
Overall change	8.08 kB	8.08 kB	✓

Client Build Manifests

	vercel/next.js canary	Timer/next.js remove/next-data	Change
_buildManifest.js gzip	323 B	323 B	✓
Overall change	323 B	323 B	✓

Rendered Page Sizes

	vercel/next.js canary	Timer/next.js remove/next-data	Change
index.html gzip	615 B	615 B	✓
link.html gzip	621 B	621 B	✓
withRouter.html gzip	607 B	607 B	✓
Overall change	1.84 kB	1.84 kB	✓

---

Serverless Mode (Decrease detected ✓)

General Overall decrease ✓

	vercel/next.js canary	Timer/next.js remove/next-data	Change
buildDuration	13.3s	13s	-255ms
nodeModulesSize	80.6 MB	80.6 MB	-7.82 kB

Client Bundles (main, webpack, commons)

	vercel/next.js canary	Timer/next.js remove/next-data	Change
677f882d2ed8..42af.js gzip	13 kB	13 kB	✓
framework.HASH.js gzip	39 kB	39 kB	✓
main-243368f..7063.js gzip	6.59 kB	6.59 kB	✓
webpack-50be..df5b.js gzip	751 B	751 B	✓
Overall change	59.3 kB	59.3 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	Timer/next.js remove/next-data	Change
polyfills-81..14d7.js gzip	31.2 kB	31.2 kB	✓
Overall change	31.2 kB	31.2 kB	✓

Client Pages

	vercel/next.js canary	Timer/next.js remove/next-data	Change
_app-b6fc6bc..222c.js gzip	1.28 kB	1.28 kB	✓
_error-cfcb6..fe1c.js gzip	3.44 kB	3.44 kB	✓
hooks-010c20..8411.js gzip	887 B	887 B	✓
index-bbee2f..528b.js gzip	227 B	227 B	✓
link-705099c..c35d.js gzip	1.64 kB	1.64 kB	✓
routerDirect..bf84.js gzip	303 B	303 B	✓
withRouter-a..5826.js gzip	302 B	302 B	✓
Overall change	8.08 kB	8.08 kB	✓

Client Build Manifests

	vercel/next.js canary	Timer/next.js remove/next-data	Change
_buildManifest.js gzip	323 B	323 B	✓
Overall change	323 B	323 B	✓

Serverless bundles

	vercel/next.js canary	Timer/next.js remove/next-data	Change
_error.js	1 MB	1 MB	✓
404.html	2.67 kB	2.67 kB	✓
hooks.html	1.92 kB	1.92 kB	✓
index.js	1 MB	1 MB	✓
link.js	1.06 MB	1.06 MB	✓
routerDirect.js	1.05 MB	1.05 MB	✓
withRouter.js	1.05 MB	1.05 MB	✓
Overall change	5.17 MB	5.17 MB	✓

Commit: 7f7f023