x/build: add LUCI linux-riscv64-rva22u64 builder

[mengzhuo]

Add 3 builders with the env GORISCV64=rva22u64 enabled

Ref #61476

CSR:

linux-riscv64-mengzhuo.csr.txt

The builder is based on SpacemiT X60 (8 cores with 8GB)

cc @golang/riscv64 @dmitshur

[gabyhelp]

Related Issues

• x/build: add LUCI linux-riscv64 builder #63481 (closed)
• x/build: add LUCI openbsd-riscv64 builder #64176 (closed)
• x/build: add LUCI freebsd-riscv64 builder #63482 (closed)
• x/build: add LUCI openbsd-riscv64 builder #67105
• x/build: add LUCI linux-ppc64le_power9 builder #66667 (closed)
• x/build: add LUCI linux-ppc64le_power10 builder #64660 (closed)
• x/build: add LUCI openbsd-arm64 builder #67104
• x/build: add LUCI linux-ppc64_power8 builder #66701 (closed)
• x/build: add LUCI linux-ppc64_power10 builder #64588 (closed)
• x/build: add LUCI openbsd-arm builder #67103

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[mengzhuo]

#78045 using the same board

[cagedmantis]

@mengzhuo There is already a certificate issued for linux-riscv64-mengzhuo. Can you please create a certificate request for linux-riscv64-rva22u64-mengzhuo?

[mengzhuo]

linux-riscv64-rva22u64-mengzhuo.csr.txt

@cagedmantis I had regenerated a csr PTAL

[dmitshur]

@mengzhuo Thanks, here's the corresponding certificate: linux-riscv64-rva22u64-mengzhuo-1774283578.cert.txt.

I expect that your 3 new builders will be able to connect with this certificate, and by default they'll be placed in the same pool as the previous 4 linux/riscv64 builders (https://chromium-swarm.appspot.com/botlist?f=cipd_platform%3Alinux-riscv64&f=pool%3Aluci.golang.shared-workers). So they'll be receiving work interchangeably with the previous linux/riscv64 builders. That seems okay to me, but if you end up wanting to separate them into separate builder definitions so each Go commit is tested separately, that would need additional builder definition changes.