"replay" test on target alpha is flaky due to RCU change

Host environment

• Operating system: Fedora 42
• OS/kernel version: 6.17
• Architecture: x86_64
• QEMU flavor: qemu-system-alpha
• QEMU version: >= 55d98e3e
• QEMU command line:

 pyvenv/bin/meson test --no-rebuild -t 1 --setup thorough \
  --num-processes 1 --repeat 10 func-alpha-replay

Emulated/Virtualized environment

• Operating system: Linux
• OS/kernel version: 2.6.26
• Architecture: alpha

Description of problem

Since commit 55d98e3e ("rcu: Unify force quiescent state") has been merged, the replay test for the alpha target got flaky and is failing with a ~ 50% chance, also causing failures in the Gitlab CI now, see e.g. https://gitlab.com/qemu-project/qemu/-/jobs/11984309870 .

Steps to reproduce

1. Run the test a couple of times (see command line above)

Additional information

See https://lore.kernel.org/qemu-devel/cb41dc20-5a87-42b6-8819-08f5a1ee4303@redhat.com for an initial discussion on the mailing list.