Update test order within gross_store_test.go to match order of steps

I was a bit confused when I went through this exercise (maps exercise called Gross Store in the Go language), I usually approach these in a TDD kind of style, where I do one step, run tests, and verify that the step is working as expected. However this exercise the tests seemed to be out of order compared to the steps.

Opened a PR here that re-arranged the order of the tests (not sure if that is the “right” fix however), it was closed and redirected me here however.

Looks like I wasn’t the only one who found the same issue and attempted to open a PR to fix either: Update gross_store_test.go by carlosalg · Pull Request #2699 · exercism/go · GitHub