Increase the timeout for worker removal under rr (#59214)
rr can make things slower, particularly under load. We saw the removal
timeout in
https://buildkite.com/julialang/julia-master-scheduled/builds/1228/steps/canvas?sid=0198793f-b191-4207-8793-a347afd2f71f
but I can't see a great rason why that happened, so let's bump the
timeout to 5 minute to give it plenty of time to exit properly.
