update tsconfig correctly when compilerOptions is not set yet

[sokra]

A tsconfig like:

{
  "extends": "..."
}

currently fails the build if the config that is extended from has not the expected configuration (and we want to update it)

Fixes: #30360

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
buildDuration	22.7s	22.7s	⚠️ +6ms
buildDurationCached	4.5s	4.4s	-108ms
nodeModulesSize	207 MB	207 MB	⚠️ +487 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
/ failed reqs	0	0	✓
/ total time (seconds)	4.064	4.021	-0.04
/ avg req/sec	615.09	621.7	+6.61
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.244	2.172	-0.07
/error-in-render avg req/sec	1114.32	1151.03	+36.71

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	28 kB	28 kB	✓
webpack-HASH.js gzip	1.45 kB	1.45 kB	✓
Overall change	71.9 kB	71.9 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
polyfills-a4..dd70.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
_app-HASH.js gzip	1.23 kB	1.23 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	4.44 kB	4.44 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	✓
334f979574ae..6f4.css gzip	106 B	106 B	✓
Overall change	13.1 kB	13.1 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
index.html gzip	535 B	535 B	✓
link.html gzip	547 B	547 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.61 kB	1.61 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
buildDuration	18.9s	18.7s	-158ms
buildDurationCached	4.5s	4.5s	⚠️ +3ms
nodeModulesSize	207 MB	207 MB	⚠️ +487 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.954	3.922	-0.03
/ avg req/sec	632.27	637.4	+5.13
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	2.132	2.189	⚠️ +0.06
/error-in-render avg req/sec	1172.54	1142.03	⚠️ -30.51

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	28.2 kB	28.2 kB	✓
webpack-HASH.js gzip	1.43 kB	1.43 kB	✓
Overall change	72 kB	72 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
polyfills-a4..dd70.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
_app-HASH.js gzip	1.22 kB	1.22 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	2.38 kB	2.38 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	621 B	621 B	✓
image-HASH.js gzip	4.46 kB	4.46 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	1.9 kB	1.9 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	✓
334f979574ae..6f4.css gzip	106 B	106 B	✓
Overall change	13.1 kB	13.1 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js bugfix/tsconfig-update	Change
index.html gzip	535 B	535 B	✓
link.html gzip	547 B	547 B	✓
withRouter.html gzip	529 B	529 B	✓
Overall change	1.61 kB	1.61 kB	✓

Commit: a71d63e