Use hasConcurrentFeatures instead of reactRoot as the condition of Fizz

[shuding]

We should use the hasConcurrentFeatures as the condition to enable Fizz, instead of reactRoot, otherwise just by installing React 18 will break stuff such as CSS imports.

Currently hasConcurrentFeatures still needs to opt-in via the global runtime option. Once we fixed all the CSS bugs and add back #35245, we can flip the condition here again.

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/1054	Change
buildDuration	15.5s	15.6s	⚠️ +74ms
buildDurationCached	6.2s	6.1s	-41ms
nodeModulesSize	456 MB	456 MB	⚠️ +32 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	shuding/next.js shu/1054	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.992	2.978	-0.01
/ avg req/sec	835.64	839.49	+3.85
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.216	1.216	✓
/error-in-render avg req/sec	2055.09	2056.73	+1.64

Client Bundles (main, webpack)

	vercel/next.js canary	shuding/next.js shu/1054	Change
925.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	28 kB	28 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.6 kB	71.6 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/1054	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/1054	Change
_app-HASH.js gzip	1.36 kB	1.36 kB	✓
_error-HASH.js gzip	192 B	192 B	✓
amp-HASH.js gzip	309 B	309 B	✓
css-HASH.js gzip	327 B	327 B	✓
dynamic-HASH.js gzip	2.57 kB	2.57 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	920 B	920 B	✓
image-HASH.js gzip	5.48 kB	5.48 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.26 kB	2.26 kB	✓
routerDirect..HASH.js gzip	320 B	320 B	✓
script-HASH.js gzip	387 B	387 B	✓
withRouter-HASH.js gzip	319 B	319 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	15.2 kB	15.2 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/1054	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/1054	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/1054	Change
buildDuration	19s	19.2s	⚠️ +215ms
buildDurationCached	6.1s	6.2s	⚠️ +6ms
nodeModulesSize	456 MB	456 MB	⚠️ +32 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	shuding/next.js shu/1054	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.999	2.974	-0.02
/ avg req/sec	833.72	840.56	+6.84
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.208	1.232	⚠️ +0.02
/error-in-render avg req/sec	2068.91	2029.79	⚠️ -39.12

Client Bundles (main, webpack)

	vercel/next.js canary	shuding/next.js shu/1054	Change
925.HASH.js gzip	178 B	178 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	28.2 kB	28.2 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	72.1 kB	72.1 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	shuding/next.js shu/1054	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/1054	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	179 B	179 B	✓
amp-HASH.js gzip	313 B	313 B	✓
css-HASH.js gzip	324 B	324 B	✓
dynamic-HASH.js gzip	2.56 kB	2.56 kB	✓
head-HASH.js gzip	351 B	351 B	✓
hooks-HASH.js gzip	921 B	921 B	✓
image-HASH.js gzip	5.59 kB	5.59 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	2.33 kB	2.33 kB	✓
routerDirect..HASH.js gzip	322 B	322 B	✓
script-HASH.js gzip	388 B	388 B	✓
withRouter-HASH.js gzip	317 B	317 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	15.3 kB	15.3 kB	✓

Client Build Manifests

	vercel/next.js canary	shuding/next.js shu/1054	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/1054	Change
index.html gzip	531 B	531 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: c610570