test_rx_queues.py::test_rx_queues[rgmii-125MHz-hp-mixed-xs2] test fails for some seeds

[shuchitak]

test_rx_queues.py::test_rx_queues[rgmii-125MHz-hp-mixed-xs2] fails intermittently, roughly about a couple of times every 10 runs.
The seed used to seed python's random number generator is generated randomly, so the test fails or passes depending on the seed. When the test fails, the DUT reports high priority packets being dropped.

I can recreate the failure with xmostest as well, running the master branch with xmostest.

If I increase the core clock freq from 500MHz to 600MHz, I can confirm that the test passes reliably, so this looks like a timing issue.

I've listed below 2 seed values, for which the test fails with pyxsim/xmostest, in case we want to recreate the failure.

seed = 1949281052092687998 # fails with pyxsim
seed = 1164115433906158532 # fails on xmostest