Add rack3 powercycle info.
Add rack3 powercycle info.

Change-Id: I76cd979d4f0aff7a9f7c64d467d712294b6b0966
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/435722
Reviewed-by: Kevin Lubick <7cdab2cfab351f23814786ba39716e90eed69047@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot