Delay prefix flushing

[huozhi]

Only happened with SSR without suspense case

Similar reason to #34474, the prefix (script parts) might be flushed during the render stream causing bad HTML. Use the same tricky to delay the prefix flushing

Expected

<div>content</div> <!-- render stream --> 
<script>...</script> <!-- prefix --> 

Observed

<!-- prefix choked the render stream --> 
<div <script>...</script> >content</div>

Test sample:
https://next-react-server-components-r5xocii9r-huozhi.vercel.app/ssr

[shuding]

Makes sense since this only happens with SSR.

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
buildDuration	14.4s	15s	⚠️ +656ms
buildDurationCached	5.7s	6s	⚠️ +276ms
nodeModulesSize	372 MB	372 MB	⚠️ +774 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.896	3.028	⚠️ +0.13
/ avg req/sec	863.4	825.56	⚠️ -37.84
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.279	1.32	⚠️ +0.04
/error-in-render avg req/sec	1953.98	1893.92	⚠️ -60.06

Client Bundles (main, webpack)

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
925.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	27.9 kB	27.9 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	huozhi/next.js fix-streaming-prefix	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	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	5.09 kB	5.09 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	14.8 kB	14.8 kB	✓

Client Build Manifests

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
index.html gzip	531 B	531 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
buildDuration	18.4s	17.1s	-1.3s
buildDurationCached	5.6s	6s	⚠️ +395ms
nodeModulesSize	372 MB	372 MB	⚠️ +774 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.077	2.96	-0.12
/ avg req/sec	812.51	844.45	+31.94
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.346	1.299	-0.05
/error-in-render avg req/sec	1857.13	1924.48	+67.35

Client Bundles (main, webpack)

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	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	72.2 kB	72.2 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	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	5.23 kB	5.23 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 kB	15 kB	✓

Client Build Manifests

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	huozhi/next.js fix-streaming-prefix	Change
index.html gzip	530 B	530 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: bcd16dc