test: fix -G=0 mode for longtest builder
test: fix -G=0 mode for longtest builder

For -G=3 for test using 'any'.

Change-Id: Ia37ee944a38be4f4330e62ad187f10f2d42e41bd
Reviewed-on: https://go-review.googlesource.com/c/go/+/365839
Trust: Dan Scales <7338a4f274e3bf1354488b9d1f344f4c9a69a8fb@google.com>
Run-TryBot: Dan Scales <7338a4f274e3bf1354488b9d1f344f4c9a69a8fb@google.com>
Reviewed-by: Cuong Manh Le <54b4457f1dff6823379654eb5867596497ba782f@gmail.com>

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