proposal: testing: Listing the topN most time-consuming test cases as the last output

[bo-er]

Every so often our team members have to check all the test cases to find the most time-consuming ones. Those time-consuming ones are generally badly designed and should not be left there, since they slow down our team's ability to move faster.
I personally believe that go test should be smart enough to list the top 10 most time-consuming test cases so that we don't have to look through the whole output( which is too long to read).
It's a tiny change that can make a lot of people's life easier.

[seankhliao]

Various testing summary proposals have been declined in the past, see #41878 and linked issues.
Building something on top of go test -json output would seem to be more appropriate for this niche usecase (you only care when they take too long).