Add deprecation warning for disabling swc minifier

[padmaia]

First is without config option enabled and second is with:

Closes WEB-1870

[vercel-spaces]

Notifying the following users due to files changed in this PR based on this repo's notify modifiers:

@timneutkens, @ijjk, @shuding, @styfle, @huozhi:

packages/next/src/server/config.ts

[ijjk]

Stats from current PR

Default Build

General Overall increase ⚠️

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
buildDuration	10.7s	10.9s	⚠️ +217ms
buildDurationCached	6.2s	6.3s	⚠️ +118ms
nodeModulesSize	175 MB	175 MB	⚠️ +1.7 kB
nextStartRea..uration (ms)	417ms	402ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
199-HASH.js gzip	32.3 kB	32.4 kB	N/A
3f784ff6-HASH.js gzip	53.2 kB	53.2 kB	N/A
99.HASH.js gzip	182 B	182 B	✓
framework-HASH.js gzip	45.5 kB	45.5 kB	✓
main-app-HASH.js gzip	251 B	251 B	✓
main-HASH.js gzip	35.3 kB	35.4 kB	N/A
webpack-HASH.js gzip	1.75 kB	1.75 kB	N/A
Overall change	46 kB	46 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
_app-HASH.js gzip	206 B	205 B	N/A
_error-HASH.js gzip	182 B	180 B	N/A
amp-HASH.js gzip	506 B	505 B	N/A
css-HASH.js gzip	322 B	323 B	N/A
dynamic-HASH.js gzip	2.59 kB	2.59 kB	✓
edge-ssr-HASH.js gzip	260 B	259 B	N/A
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	369 B	369 B	✓
image-HASH.js gzip	4.38 kB	4.38 kB	N/A
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.67 kB	2.67 kB	N/A
routerDirect..HASH.js gzip	316 B	318 B	N/A
script-HASH.js gzip	385 B	384 B	N/A
withRouter-HASH.js gzip	319 B	319 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	3.99 kB	3.99 kB	✓

Client Build Manifests

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
_buildManifest.js gzip	484 B	482 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
index.html gzip	528 B	529 B	N/A
link.html gzip	542 B	542 B	✓
withRouter.html gzip	524 B	524 B	✓
Overall change	1.07 kB	1.07 kB	✓

Edge SSR bundle Size

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
edge-ssr.js gzip	96 kB	96 kB	N/A
page.js gzip	140 kB	140 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	padmaia/next.js deprecate-terser	Change
middleware-b..fest.js gzip	625 B	621 B	N/A
middleware-r..fest.js gzip	150 B	151 B	N/A
middleware.js gzip	25.6 kB	25.6 kB	N/A
edge-runtime..pack.js gzip	1.92 kB	1.92 kB	✓
Overall change	1.92 kB	1.92 kB	✓

Commit: a13616d