Clarify TestRateLimit (#649)
Clarify TestRateLimit (#649)

* Switch to fortio for RateLimit testing

* simplify test condition

* Update to HTTPRunner

* prefer 8 to 10

* Update to add clarity

* More improvements

* Add longer sleeps to give time for routing rules to take effect

* Minor updates

sebrandon1/istio,sebrandon1/istio,sebrandon1/istio,sebrandon1/istio