autopkgtest i386 doesn't work for experimental

Thanks for i386 autopkgtest! It seems to work fine for a couple of packages I used it on so far.

However I just prepared an upload to experimental, and it seems the job is missing some support for experimental, job log here:

https://salsa.debian.org/jas/golang-github-go-piv-piv-go/-/jobs/8148566

$ LOCAL_ARCH="$(dpkg --print-architecture)"
$ LXC_JOB_NAME="${RELEASE}"
$ test "${LOCAL_ARCH}" = "amd64" || LXC_JOB_NAME="${RELEASE}_${LOCAL_ARCH}"
$ wget --progress=dot:giga ${SALSA_CI_AUTOPKGTEST_LXC}/-/jobs/artifacts/master/raw/artifacts/lxc-${LOCAL_ARCH}.tar?job=${LXC_JOB_NAME} -O lxc.tar
--2025-08-30 07:41:28--  https://salsa.debian.org/salsa-ci-team/autopkgtest-lxc/-/jobs/artifacts/master/raw/artifacts/lxc-i386.tar?job=experimental_i386
Resolving salsa.debian.org (salsa.debian.org)... 209.87.16.44, 2607:f8f0:614:1::1274:44
Connecting to salsa.debian.org (salsa.debian.org)|209.87.16.44|:443... connected.
HTTP request sent, awaiting response... 404 Not Found
2025-08-30 07:41:28 ERROR 404: Not Found.