Should we have a 'test' jenkins server for experiments?

I need to request a new machine:

- New machine operating system (e.g. linux/windows/macos/solaris/aix): Probably linux
- New machine architecture (e.g. x64/aarch32/arm32/ppc64/ppc64le/sparc): Doesn't matter
- Provider (leave blank if it does not matter):
- Desired usage: Test jenkins server
- Any unusual specification/setup required: jenkins :-)
- How many of them are required: 1

Please explain what this machine is needed for:
- Initially proposed in https://github.com/adoptium/infrastructure/issues/2108 it would be useful to have a second server for people to experiment with before deploying to our production one. This may also allow us to restrict the access controls on the production server a bit more.

We would need to give careful consideration to:
- How many of the jobs are "live" on the test server (We would probably not want them triggering full build pipelines every day)
- Which nodes to attach to them (We don't want it to conflict with the production server)
- Which secrets will be available to jobs running on the server

Start with the proposal referenced in issue #2108. Define the test server's operating system and provider, which jobs and nodes it may use, and which secrets are permitted; done means one isolated Jenkins test server can support experiments without conflicting with production.

Written by the indexing model from the issue text.