Update dist-various linux-gnu target baselines

[cuviper]

These Tier 2 non-host targets were affected by the update to
ubuntu:22.04 in #113931, but the platform support page was already out
of date after #81521 updated to ubuntu:20.04. They are now listed for
kernel 5.15 and glibc 2.35 as found in 22.04, and a new footnote
mentions that this only matters when using the dynamic libstd.so.

r? @Mark-Simulacrum

[nikic]

Hm, does the kernel of the host matter for libstd.so? Aren't kernel differences handled at runtime? I'd expect the kernel requirement to always be the lowest overall supported version (apart from target specific requirements, e.g. for newer arches).

[Mark-Simulacrum]

Yeah, I'd also expect similar. Kernel 5.15 is comparatively very recent -- I'd be surprised if we actually relied on that version here.

[bors]

☔ The latest upstream changes (presumably #116372) made this pull request unmergeable. Please resolve the merge conflicts.

[oskgo]

@cuviper Any updates on this? Thanks

[cuviper]

I don't have any update, but your ping has bubbled this back up my to-do list, so I'll try to revisit it soon.

[JohnCSimon]

@cuviper

Ping from triage: I'm closing this due to inactivity, Please reopen when you are ready to continue with this.
Note: if you are going to continue please open the PR BEFORE you push to it, else you won't be able to reopen - this is a quirk of github.
Thanks for your contribution.

@rustbot label: +S-inactive