x/build: add LUCI openbsd-riscv64 builder

[4a6f656c]

Please add a LUCI builder for openbsd/riscv64 with hostname openbsd-riscv64-jsing - note that this will be running on the same hardware as the current host-openbsd-riscv64-joelsing builder. This machine is unlikely to be capable of running both forms and will need to be hard migrated at some point in time. CSR for this builder is attached.

openbsd-riscv64-jsing.csr.txt

[gopherbot]

Change https://go.dev/cl/584777 mentions this issue: main.star: update openbsd-{arm,arm64,riscv64} builder configurations

[dmitshur]

Here's the certificate: openbsd-riscv64-jsing-1715630475.cert.txt.

Please feel free to stop the old coordinator builder on your end whenever it's getting in the way of bringing up the new LUCI builder.

[4a6f656c]

@dmitshur - thanks, this one should be up and running, although I have no idea how to confirm this (it logs nothing except for the occasional RPC error).

[dmitshur]

Thanks for setting it up! I see it at https://ci.chromium.org/ui/p/golang/builders/luci.golang.ci/gotip-openbsd-riscv64?limit=200 and https://chromium-swarm.appspot.com/bot?id=openbsd-riscv64-jsing (the latter link requires signing in to view, any account will work). In a recent build like https://ci.chromium.org/b/8747215393872298177, I see it failed during cipd ensure on fetching the bootstrap toolchain. Sent CL 588356 for that.

[gopherbot]

Change https://go.dev/cl/588356 mentions this issue: main.star: use gotip-ish as bootstrap for openbsd/riscv64