Fix static file check with i18n

[ijjk]

This ensures we properly 404 when a static asset e.g. _next/static/ is requested with a locale prefix and adds test cases ensuring we don't regress on this behavior.

Bug

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

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
buildDuration	14.2s	14.1s	-131ms
buildDurationCached	3.6s	3.7s	⚠️ +64ms
nodeModulesSize	355 MB	355 MB	⚠️ +1.18 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.368	3.327	-0.04
/ avg req/sec	742.28	751.45	+9.17
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.533	1.568	⚠️ +0.04
/error-in-render avg req/sec	1631.28	1594.68	⚠️ -36.6

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	27.2 kB	27.2 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71 kB	71 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	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	326 B	326 B	✓
dynamic-HASH.js gzip	2.37 kB	2.37 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	919 B	919 B	✓
image-HASH.js gzip	4.87 kB	4.87 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.13 kB	2.13 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	14.2 kB	14.2 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
index.html gzip	531 B	531 B	✓
link.html gzip	546 B	546 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
buildDuration	18.6s	18.6s	-84ms
buildDurationCached	3.8s	3.8s	⚠️ +48ms
nodeModulesSize	355 MB	355 MB	⚠️ +1.18 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.564	3.509	-0.06
/ avg req/sec	701.55	712.47	+10.92
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.601	1.674	⚠️ +0.07
/error-in-render avg req/sec	1561.63	1493.62	⚠️ -68.01

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.3 kB	42.3 kB	✓
main-HASH.js gzip	27.3 kB	27.3 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.3 kB	71.3 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	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	2.36 kB	2.36 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	911 B	911 B	✓
image-HASH.js gzip	4.89 kB	4.89 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.19 kB	2.19 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	14.2 kB	14.2 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js fix/i18n-static-file-check	Change
index.html gzip	530 B	530 B	✓
link.html gzip	544 B	544 B	✓
withRouter.html gzip	525 B	525 B	✓
Overall change	1.6 kB	1.6 kB	✓

Commit: 397988f