Use partial clone for setting up as-if-jh branch

What does this MR do and why?

Use partial clone for setting up as-if-jh branch

Try strategy mentioned at: #390409 (comment 1309535566)

Approach in this merge request (GIT_STRATEGY set to none and clone with --filter=tree:0)

About 2 minutes for the job with 4 samples:

• https://gitlab.com/gitlab-org/gitlab/-/jobs/3931319018 (1m56s)
• https://gitlab.com/gitlab-org/gitlab/-/jobs/3932353911 (1m52s)
• https://gitlab.com/gitlab-org/gitlab/-/jobs/3938629261 (2m4s)
• https://gitlab.com/gitlab-org/gitlab/-/jobs/3938683362 (1m45s)

Slightly slower but potentially more reliable.

Approach before this merge request (GIT_DEPTH set to 20 and use git fetch --unshallow --filter=tree:0)

About 1.5 minutes:

• https://gitlab.com/gitlab-org/gitlab/-/jobs/3926123139 (1m21s)

Occasionally we see this error: #390409 (closed)

Interestingly, it's been awhile since last time I saw this error!

Approach with full clone (GIT_DEPTH set to 0)

About 5 minutes:

• https://gitlab.com/gitlab-org/gitlab/-/jobs/3907095733 (5m15s)

Related to #390409 (closed)