[release-branch.go1.21] internal/testenv: support the LUCI mobile builders in tests
This change updates the testenv tests to correctly match on future LUCI
builder names for mobile builders. This isn't a problem today because
those haven't been set up yet, but the builder names are structured and
it's clear where the modifiers will appear. Might as well set them up
now.
For #65473.
Fixes #65475.
Change-Id: I244b88a62a90312c0f3ff2360527d58531070362
Reviewed-on: https://go-review.googlesource.com/c/go/+/558597
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
(cherry picked from commit
5c7c24ce827b10982245951f6c2b1bbf0abc5aae)
Reviewed-on: https://go-review.googlesource.com/c/go/+/560895