Improve ProxyHandler benchmark (#9126)
Improve ProxyHandler benchmark (#9126)

* Remove distracting stats reporting from test

The reporting period is a second. Go runs benchmarks by default as many
times as it can within one second. This means _most_ of the time Report
never runs, and when it does run it's an artifact of test timings, not
the actual speed of the code.

* Make Report actually do something

* consistency
knative/serving,knative/serving