test/typeparam: adjust test preamble (fix longtests)
test/typeparam: adjust test preamble (fix longtests)

For #50317.

Change-Id: I24ccf333c380283a36b573ef8fc3e7fcd71bd17f
Reviewed-on: https://go-review.googlesource.com/c/go/+/376215
Trust: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>
Run-TryBot: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>
Reviewed-by: Dan Scales <7338a4f274e3bf1354488b9d1f344f4c9a69a8fb@google.com>
Trust: Dan Scales <7338a4f274e3bf1354488b9d1f344f4c9a69a8fb@google.com>

cloudflare/go,golang/go,cloudflare/go,nawawi/go,cloudflare/go,CAFxX/go,nawawi/go,nawawi/go,golang/go,cloudflare/go,golang/go,cloudflare/go,CAFxX/go,nawawi/go,nawawi/go,nawawi/go,CAFxX/go,nawawi/go,cloudflare/go,CAFxX/go,CAFxX/go,nawawi/go,cloudflare/go,golang/go,CAFxX/go,golang/go,CAFxX/go,golang/go,golang/go,golang/go,CAFxX/go,cloudflare/go