Improve TestGetDistForGoals debuggability

Previously, TestGetDistForGoals tested multiple test cases within a
single test so when it failed it was difficult to determine which test
case was the cause. This change runs each test case as its own
nested test.

It also corrects the order of expectedLine and line format parameters
to match the order in the message.

Test: m nothing
Bug: 174226317
Change-Id: I1408ec4125afc5c0b392cd7643dd3f630fe468e5