test: widen cluster shutdownAll await for aeron-udp drain on JDK 25 nightly

[He-Pin]

Motivation

MixedProtocolClusterSpec "be allowed to join a cluster with a node using the pekko protocol (udp)" still fails on virtualized JDK 25 runs after #2997 reordered shutdownAll to stop joining nodes first:

[WARN] CoordinatedShutdown(pekko://MixedProtocolClusterSpec) Coordinated
shutdown phase [actor-system-terminate] timed out after 30000 milliseconds
java.lang.RuntimeException: Failed to stop [MixedProtocolClusterSpec] within [1 minute]
 ... StreamSupervisor ... remote-6-0-unnamed ActorGraphInterpreter

The "within [1 minute]" outer await is a 30s base dilated by pekko.test.timefactor — i.e. this lane runs at tf=2 (30s × 2 = 60s). The JDK 25 nightly runs at tf=4 → 120s and passes.

The actor-system-terminate phase only calls system.finalTerminate() and recovers on its own (non-dilated) phase timeout while termination keeps draining in the background (CoordinatedShutdown.scala:264-269). So the inner-phase WARN is non-binding noise — ClusterTestUtil.shutdownAll's dilated await on whenTerminated is the real pass/fail deadline. The aeron-udp transport is the slowest to drain (embedded media driver + stacked Aeron liveness timeouts), so 60s was simply too tight at tf=2.

Modification

• ClusterTestUtil.shutdownAll: raise the outer await base 30s → 60s (the binding, timefactor-dilated deadline), so a tf=2 lane gets ~120s — the same headroom the tf=4 nightly already passes with. Added a comment explaining why this await, not the inner phase, governs pass/fail.
• MixedProtocolClusterSpec baseConfig: raise the (non-dilated, non-binding) actor-system-terminate phase timeout 30s → 60s to suppress the spurious WARN on the slow path and align it with the new await base.

This is a follow-up to #2997 — that PR pulled the shutdown-ordering lever; this one fixes the binding outer-await deadline.

Result

aeron-udp cluster systems get enough wall-clock to terminate cleanly on lower-timefactor virtualized lanes without the shutdown-phase abort. Healthy shutdowns still complete in well under a second, so local and normal CI runs are unaffected. Test-only change — no production behaviour or binary-compatibility impact.

Tests

• sbt "cluster/Test/compile" — success (cluster test-classes compiled)
• scalafmt 3.10.7 on both changed files — no reformatting needed
• git diff --check — clean
• aeron-udp shutdown timing is timefactor/environment dependent and does not reproduce on local runs (shutdown completes <1s); the change is a timeout widening verified by compile + format.

References

• Follow-up to test: shut down cluster test systems in reverse order #2997 (reverse-order cluster shutdown)
• nightly-builds.yml MixedProtocolClusterSpec (udp) shutdown timeout