Use the serverless page handler in the web runtime

[shuding]

Related to #31506:

Update the middleware SSR loader to reuse the serverless page handler and share the logic of rewrite/dynamic routes/i18n handling logic

This PR added WebIncomingMessage and WebServerResponse interfaces as the "bridge", this is critical for the switchable runtimes. Note that this is just an initial and incomplete implementation specifically for renderToHTML to be used in the web runtime. Will later improve it incrementally.

On top of that, the SSR middleware now uses the full page handler so it should be able to handle dynamic routes (locales and rewrites to be fixed soon).

Bug

• Related issues linked using fixes #number
• Integration tests added
• Errors have helpful link attached, see contributing.md

Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• Related issues linked using fixes #number
• Integration tests added
• Documentation added
• Telemetry added. In case of a feature if it's used or not.
• Errors have helpful link attached, see contributing.md

Documentation / Examples

• Make sure the linting passes by running yarn lint

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
buildDuration	17.8s	18.1s	⚠️ +257ms
buildDurationCached	3.3s	3.4s	⚠️ +20ms
nodeModulesSize	346 MB	346 MB	⚠️ +11 kB

Page Load Tests Overall increase ✓

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.939	2.961	⚠️ +0.02
/ avg req/sec	850.57	844.34	⚠️ -6.23
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.406	1.373	-0.03
/error-in-render avg req/sec	1777.8	1821.05	+43.25

Client Bundles (main, webpack, commons)

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	28.4 kB	28.4 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.2 kB	72.2 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
_app-HASH.js gzip	1.37 kB	1.37 kB	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	2.38 kB	2.38 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	635 B	635 B	✓
image-HASH.js gzip	4.45 kB	4.45 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	1.87 kB	1.87 kB	✓
routerDirect..HASH.js gzip	321 B	321 B	✓
script-HASH.js gzip	383 B	383 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	13.3 kB	13.3 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
index.html gzip	532 B	532 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
buildDuration	19.6s	19.9s	⚠️ +256ms
buildDurationCached	3.4s	3.4s	-3ms
nodeModulesSize	346 MB	346 MB	⚠️ +11 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.88	2.942	⚠️ +0.06
/ avg req/sec	868.17	849.66	⚠️ -18.51
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.362	1.36	0
/error-in-render avg req/sec	1836.13	1837.85	+1.72

Client Bundles (main, webpack, commons)

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.6 kB	28.6 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	72.5 kB	72.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	180 B	180 B	✓
amp-HASH.js gzip	305 B	305 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.37 kB	2.37 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	622 B	622 B	✓
image-HASH.js gzip	4.47 kB	4.47 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	1.91 kB	1.91 kB	✓
routerDirect..HASH.js gzip	314 B	314 B	✓
script-HASH.js gzip	375 B	375 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	13.2 kB	13.2 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
_buildManifest.js gzip	458 B	458 B	✓
Overall change	458 B	458 B	✓

Rendered Page Sizes

	vercel/next.js canary	shuding/next.js shu/b2ce	Change
index.html gzip	532 B	532 B	✓
link.html gzip	544 B	544 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: 9957e94