[perf] Fix height of plot.
[perf] Fix height of plot.

Change-Id: Idc935fce169ca1006defe4ca5912424be476195b
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/269477
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@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