Fix weekly test runs

[smlambert]

Partial fix for #857

• keep Junit results for dev.functional
• only run dev.openjdk and sanity.external on x64Linux (for now)

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[karianna]

@smlambert This will nee a rebase

[github-actions]

A block has been put on this Pull Request as this repository is temporarily under a code freeze due to an ongoing release cycle.

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[sophia-guo]

As discussed reproduce compare jobs will move to dev.system category adoptium/temurin-build#3587, could you please add dev.system to weekly test list for jdk21+ linux related platforms?

[karianna]

/thaw

Pull Request unblocked - code freeze is over.

[karianna]

@smlambert Unlovcked but will still need a rebase

[smlambert]

Close this in favour of #929