cmd/dist: refactor adding to the test list into a method
Currently, there are four places that add distTests to the
tester.tests list. That means we're already missing a few name
uniqueness checks, and we're about to start enforcing some more
requirements on tests that would be nice to have in one place. Hence,
to prepare for this, this CL refactors the process of adding to the
tester.tests list into a method. That also means we can trivially use
a map to check name uniqueness rather than an n^2 slice search.
For #37486.
Change-Id: Ib7b64c7bbf65e5e870c4f4bfaca8c7f70983605c
Reviewed-on: https://go-review.googlesource.com/c/go/+/495015
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>