Introduce react profiling production flag

[todortotev]

Closes 13709.

The solution works, (tested and confirmed with true and false flags with the latest next version) though I am quite sure this is not the most elegant and proper way to implement it. I have spent the good part of yesterday and today's morning in order to make it more generic but since it's my first time working with anything related to webpack I have struggled miserably. Last, but not least I'm unsure if this is the most proper naming for the flag.

Please, let me know what you want me to change and I'll get it done asap.

[ijjk]

Stats from current PR

Default Server Mode (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
buildDuration	12.2s	12.3s	⚠️ +37ms
nodeModulesSize	66 MB	66 MB	⚠️ +944 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.094	2.088	-0.01
/ avg req/sec	1193.95	1197.22	⚠️ +3.27
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.127	1.217	⚠️ +0.09
/error-in-render avg req/sec	2217.37	2055.05	-162.32

Client Bundles (main, webpack, commons)

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
main-HASH.js gzip	6.59 kB	6.59 kB	✓
webpack-HASH.js gzip	746 B	746 B	✓
de003c3a9d30..6c2a.js gzip	10.5 kB	10.5 kB	✓
framework.HASH.js gzip	39.1 kB	39.1 kB	✓
Overall change	57 kB	57 kB	✓

Client Bundles (main, webpack, commons) Modern

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
main-HASH.module.js gzip	5.67 kB	5.67 kB	✓
webpack-HASH..dule.js gzip	746 B	746 B	✓
de003c3a9d30..dule.js gzip	6.93 kB	6.93 kB	✓
framework.HA..dule.js gzip	39.1 kB	39.1 kB	✓
Overall change	52.5 kB	52.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
polyfills-HASH.js gzip	26.3 kB	26.3 kB	✓
Overall change	26.3 kB	26.3 kB	✓

Client Pages

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_app.js gzip	1.26 kB	1.26 kB	✓
_error.js gzip	3.25 kB	3.25 kB	✓
hooks.js gzip	881 B	881 B	✓
index.js gzip	222 B	222 B	✓
link.js gzip	2.05 kB	2.05 kB	✓
routerDirect.js gzip	279 B	279 B	✓
withRouter.js gzip	278 B	278 B	✓
Overall change	8.21 kB	8.21 kB	✓

Client Pages Modern

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_app.module.js gzip	604 B	604 B	✓
_error.module.js gzip	2.04 kB	2.04 kB	✓
hooks.module.js gzip	383 B	383 B	✓
index.module.js gzip	223 B	223 B	✓
link.module.js gzip	1.51 kB	1.51 kB	✓
routerDirect..dule.js gzip	281 B	281 B	✓
withRouter.m..dule.js gzip	278 B	278 B	✓
Overall change	5.32 kB	5.32 kB	✓

Client Build Manifests

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_buildManifest.js gzip	61 B	61 B	✓
_buildManife..dule.js gzip	61 B	61 B	✓
Overall change	122 B	122 B	✓

Rendered Page Sizes

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
index.html gzip	924 B	924 B	✓
link.html gzip	934 B	934 B	✓
withRouter.html gzip	922 B	922 B	✓
Overall change	2.78 kB	2.78 kB	✓

---

Serverless Mode

General Overall increase ⚠️

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
buildDuration	13.4s	13.5s	⚠️ +89ms
nodeModulesSize	66 MB	66 MB	⚠️ +944 B

Client Bundles (main, webpack, commons)

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
main-HASH.js gzip	6.59 kB	6.59 kB	✓
webpack-HASH.js gzip	746 B	746 B	✓
de003c3a9d30..6c2a.js gzip	10.5 kB	10.5 kB	✓
framework.HASH.js gzip	39.1 kB	39.1 kB	✓
Overall change	57 kB	57 kB	✓

Client Bundles (main, webpack, commons) Modern

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
main-HASH.module.js gzip	5.67 kB	5.67 kB	✓
webpack-HASH..dule.js gzip	746 B	746 B	✓
de003c3a9d30..dule.js gzip	6.93 kB	6.93 kB	✓
framework.HA..dule.js gzip	39.1 kB	39.1 kB	✓
Overall change	52.5 kB	52.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
polyfills-HASH.js gzip	26.3 kB	26.3 kB	✓
Overall change	26.3 kB	26.3 kB	✓

Client Pages

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_app.js gzip	1.26 kB	1.26 kB	✓
_error.js gzip	3.25 kB	3.25 kB	✓
hooks.js gzip	881 B	881 B	✓
index.js gzip	222 B	222 B	✓
link.js gzip	2.05 kB	2.05 kB	✓
routerDirect.js gzip	279 B	279 B	✓
withRouter.js gzip	278 B	278 B	✓
Overall change	8.21 kB	8.21 kB	✓

Client Pages Modern

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_app.module.js gzip	604 B	604 B	✓
_error.module.js gzip	2.04 kB	2.04 kB	✓
hooks.module.js gzip	383 B	383 B	✓
index.module.js gzip	223 B	223 B	✓
link.module.js gzip	1.51 kB	1.51 kB	✓
routerDirect..dule.js gzip	281 B	281 B	✓
withRouter.m..dule.js gzip	278 B	278 B	✓
Overall change	5.32 kB	5.32 kB	✓

Client Build Manifests

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_buildManifest.js gzip	61 B	61 B	✓
_buildManife..dule.js gzip	61 B	61 B	✓
Overall change	122 B	122 B	✓

Serverless bundles

	vercel/next.js canary	TodorTotev/next.js introduce-react-profiling-production-flag	Change
_error.js	878 kB	878 kB	✓
404.html	4.18 kB	4.18 kB	✓
hooks.html	3.81 kB	3.81 kB	✓
index.js	879 kB	879 kB	✓
link.js	916 kB	916 kB	✓
routerDirect.js	909 kB	909 kB	✓
withRouter.js	909 kB	909 kB	✓
Overall change	4.5 MB	4.5 MB	✓