internal/relui: don't run TryBots with known issues
internal/relui: don't run TryBots with known issues

The AWS Macs are offline indefinitely and blocking the release. When I
originally wrote the TryBot check I thought KIs would be transient and
it'd be useful to see their results, but in practice we have builders
broken in various ways for months. So just skip them.

Maybe a more sophisticated approach where we try them and ignore errors
would be better but I don't feel like working through it.

Change-Id: I14c982acdc7ee721f91436b33784cf693b860f4b
Reviewed-on: https://go-review.googlesource.com/c/build/+/445615
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@google.com>
Auto-Submit: Heschi Kreinick <e89ab2b172855aa0ad01c40c4d8a3535a61ac68a@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Run-TryBot: Heschi Kreinick <e89ab2b172855aa0ad01c40c4d8a3535a61ac68a@google.com>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>

golang/build,golang/build,golang/build,golang/build