Add failing test for stuck Suspense fallback

[gaearon]

Another issue that was discovered in #14073 (comment) (although this one is specific to concurrent mode). This just looks like a bug.

Setting second child's ms lower does not reproduce it.

[gaearon]

Might be the same problem as #14013? Don't know.

[sizebot]

Details of bundled changes.

Comparing: c84b9bf...06433bb

scheduler

File	Filesize Diff	Gzip Diff	Prev Size	Current Size	Prev Gzip	Current Gzip	ENV
scheduler.development.js	n/a	n/a	0 B	19.17 KB	0 B	5.74 KB	UMD_DEV
scheduler.production.min.js	n/a	n/a	0 B	3.16 KB	0 B	1.53 KB	UMD_PROD

Generated by 🚫 dangerJS

[sophiebits]

What is supposed to set .alreadyCaptured to false? It seems like once it gets set to true, the only thing that can set it back to false (and thus trigger a retry of the primary content) is the commit phase, which never runs for a suspended update. Not sure if I'm missing some part of the model in my head.

cc @acdlite

[sophiebits]

Might be the same problem as #14013? Don't know.

Looks like it. Seems like once something pings once in concurrent mode, further pings end up being no-ops.

[acdlite]

Fixed by #14083