Fix flake(s) in rabbit_fifo_int_SUITE (backport #13648) (backport #13651)

[mergify]

The start_cluster helper used the same UID (!!) for all members in the local cluster. This resulted in shared mem tables and all sorts of havoc.

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This is an automatic backport of pull request #13648 done by [Mergify](https://mergify.com).

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This is an automatic backport of pull request #13651 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 7899349 has failed:

On branch mergify/bp/v4.0.x/pr-13651
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	both modified:   deps/rabbit/test/rabbit_fifo_int_SUITE.erl

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