Refine selective page building

[Timer]

This drops the experimental setting for sharedRuntime and automatically toggles it when you utilize the --experimental-flag option on next build.

Using these changes, users can build bundles for specific subsets of page(s) and stitch the applications together.

[github-actions]

Stats from current PR

Click to expand stats

	zeit/next.js canary	Timer/next.js refine-page-building-behavior	Change
Build Duration	14.5s	13.3s	-1.3s
Client _app Size	2.49 kB	2.49 kB	✓
Client _app gzip Size	1.04 kB	1.04 kB	✓
Client _error Size	8.85 kB	8.85 kB	✓
Client _error gzip Size	3.31 kB	3.31 kB	✓
Client pages/index Size	298 B	298 B	✓
Client pages/index gzip Size	235 B	235 B	✓
Client pages/link Size	3.28 kB	3.28 kB	✓
Client pages/link gzip Size	1.49 kB	1.49 kB	✓
Client pages/routerDirect Size	426 B	426 B	✓
Client pages/routerDirect gzip Size	304 B	304 B	✓
Client pages/withRouter Size	408 B	408 B	✓
Client pages/withRouter gzip Size	293 B	293 B	✓
Client main Size	22.9 kB	22.9 kB	✓
Client main gzip Size	7.34 kB	7.34 kB	✓
Client commons Size	182 kB	182 kB	✓
Client commons gzip Size	59.4 kB	59.4 kB	✓
Client webpack Size	1.49 kB	1.49 kB	✓
Client webpack gzip Size	774 B	774 B	✓
Base Rendered Size	1.32 kB	1.32 kB	✓
Total Bundle (main, webpack, commons) Size	208 kB	208 kB	✓
Total Bundle (main, webpack, commons) gzip Size	68 kB	68 kB	✓
Build Dir Size	345 kB	345 kB	✓
node_modules Size	81.9 MB	81.9 MB	⚠️ +3.02 kB

Click to expand serverless stats

	zeit/next.js canary	Timer/next.js refine-page-building-behavior	Change
Build Duration	17.5s	17.6s	⚠️ +96ms
Client _app Size	2.49 kB	2.49 kB	✓
Client _app gzip Size	1.04 kB	1.04 kB	✓
Client _error Size	8.85 kB	8.85 kB	✓
Client _error gzip Size	3.31 kB	3.31 kB	✓
Client pages/index Size	298 B	298 B	✓
Client pages/index gzip Size	235 B	235 B	✓
Client pages/link Size	3.28 kB	3.28 kB	✓
Client pages/link gzip Size	1.49 kB	1.49 kB	✓
Client pages/routerDirect Size	426 B	426 B	✓
Client pages/routerDirect gzip Size	304 B	304 B	✓
Client pages/withRouter Size	408 B	408 B	✓
Client pages/withRouter gzip Size	293 B	293 B	✓
Client main Size	22.9 kB	22.9 kB	✓
Client main gzip Size	7.34 kB	7.34 kB	✓
Client commons Size	182 kB	182 kB	✓
Client commons gzip Size	59.4 kB	59.4 kB	✓
Client webpack Size	1.49 kB	1.49 kB	✓
Client webpack gzip Size	774 B	774 B	✓
Serverless pages/link Size	225 kB	225 kB	✓
Serverless pages/link gzip Size	59 kB	59 kB	-3 B
Serverless pages/index Size	220 kB	220 kB	✓
Serverless pages/index gzip Size	57.8 kB	57.8 kB	-1 B
Serverless pages/_error Size	222 kB	222 kB	✓
Serverless pages/_error gzip Size	57.8 kB	57.8 kB	-3 B
Serverless pages/routerDirect Size	221 kB	221 kB	✓
Serverless pages/routerDirect gzip Size	57.8 kB	57.8 kB	-1 B
Serverless pages/withRouter Size	221 kB	221 kB	✓
Serverless pages/withRouter gzip Size	57.8 kB	57.8 kB	-2 B
Total Bundle (main, webpack, commons) Size	208 kB	208 kB	✓
Total Bundle (main, webpack, commons) gzip Size	68 kB	68 kB	✓
Build Dir Size	1.33 MB	1.33 MB	✓
node_modules Size	81.9 MB	81.9 MB	⚠️ +3.02 kB