[TF-M] Possible race condition in IRQ_TEST_SCENARIO_4?

How is the IRQ_TEST_SCENARIO_4 supposed to work?

I suspect that there might be a lurking race condition somewhere in that test.

Some, not all, of the (M33/M23) targets gets stuck in that test when the ConfigRegression.cmake config is built with IAR in Debug mode. If I build it with RelWithDebInfo then the test runs OK for all applicable targets. No problems with Debug builds for the other configurations.

Occasionally the test will run successfully also for a normally problematic target if I run it in the debugger and stop execution at breakpoints, but it is very random, which is why I suspect there might be a race problem.

Thomas