tests: Integration test flag

[ValarDragon]

We should use an integration test flag in alot of locations. The integration test build flag is described more here: https://medium.com/@povilasve/go-advanced-tips-tricks-a872503ac859

This gives us a good way to take care of slower integration tests, and testing long test vectors. If possible, I think we should have CircleCI run this on every PR to master. (Presuming we're restoring the develop branch, I'm not at all sure where we are on that decision)

Suggestions for things to move to an integration test flag:

• crypto/keys - fundraiser test compatiblity. 90% of code changes likely have no chance of affecting this. We can have a quicker test of like 10 that runs on the normal go test, and run all 1000 on this flag. Would save a non-negligible amount of time.
• Long running randomized test apps. Ideally we would be running multiple different configurations

[rigelrozanski]

Good idea - interestingly this is a good arg for restoring develop/master pair.. But then again we could always run the integration tests on all PRs to a branch named integration which we just leave an open PR from master to integration on

[jackzampolin]

We have a different method for our test suite. Going to go ahead and close this.