Tests seem slow: profile test execution

[acmcarther]

The test suite seems to me to take too long to run. I'm unsure if its on the gherkin interpreter side or our side.

This is based on my usage in space_coop's client I'm inclined to believe its on the ruby end, but we should profile a set of roughly equivalent tests that run with either straight ruby or with our rust adapter.

If it turns out that its ruby thats slow, that might add impetus to writing the gherkin parser to get us unplugged from ruby. Theres a lot of hoops to jump through for that though, least of which is integrating with the Cucumber folks since they've got infrastructure for maintaining the different libraries.