dashboard: add a new wsl builder to improve service availability
dashboard: add a new wsl builder to improve service availability

For golang/go#17365

Change-Id: Icf776550e3f17d86bf0f74d5598912fe1a18cb50
Reviewed-on: https://go-review.googlesource.com/c/build/+/278874
Run-TryBot: Baokun Lee <b86f6db284d374188d561d46b45b188d5631609a@golangcn.org>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Bryan C. Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Reviewed-by: Meng Zhuo <3e6d300a356a3b86bc195677414a9ec5508ca893@golangcn.org>
Reviewed-by: Carlos Amedee <ab5e2bca84933118bbc9d48ffaccce3bac4eeb64@golang.org>
Trust: Bryan C. Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>

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