x/build: gotip-ios-amd64 and gotip-ios-arm64 SlowBots always fail

[FiloSottile]

See https://cr-buildbucket.appspot.com/build/8754129201848019169 and https://cr-buildbucket.appspot.com/build/8754129201848019153 from https://go.dev/cl/569655, which would really need testing on iOS.

[prattmic]

iOS builders haven't yet been added to LUCI, see the known issue dashboard: https://ci.chromium.org/p/golang/g/go-gotip-known_issue/console

(I think we also wanted to remove these builders from the "choose tryjobs" UI to make this less confusing. @mknyszek)

So you'll need to use the old slow bots (same as usual, TRY= and Run-TryBots+1).

Unfortunately, that iOS builder has been continuously failing for months (#61446). It tends to make it through the crypto packages though, so it may be good enough for your needs...

[mknyszek]

Yeah, I have a TODO to move the "known issue" builders out of that list. Sorry about the delay there.