Don't alert when the row/stmt is stored in a struct

[nirhaas]

• In attempt to avoid an alert on a Prepared Statement not closed (which is for a good reason, it is being re-used as intended), I added the logic to not alert when the target is stored in a struct.
  • This logic is not perfect. It would be better if we check the lifetime of the struct as well, or that the function itself that is storing is a struct method. I don't have much experience with analyzing SSA so if this needs some improvements, let me know.
• Changes to Makefile to allow make test without go install.

[ryanrolds]

Thank you. Merged and in the pre-release.