Add ACs for correctly updating program benefits on a program update

[cdummett]

Background

In core currently there is a bug where if a program is enacted in epoch K, the program is correctly updated in K + 1 but benefit factors aren't updated un till K + 2.

ACs did not capture the issue as tests simply checked if the program was correctly updated which it was rather than checking the benefits.

Summary

Check specs are clear on behaviour and add acceptance criteria to test...

• if a program is updated in epoch K, in epoch K + 1, the program is FIRST updated and then factors are ALSO set using updated benefits.
  • referral program
  • volume discount program
  • volume rebate program

Everything should now happen when an engine is notified of the start of the epoch rather then the end, as such tests checking look back windows should be verified for changes to check we are not off by one.