validation: Test rtems_interrupt_handler_iterate()

Update #3269.

spec/build/testsuites/validation/validation-0.yml

@@ -20,6 +20,7 @@ source:
 - testsuites/validation/tc-intr-entry-remove.c
 - testsuites/validation/tc-intr-get-affinity.c
 - testsuites/validation/tc-intr-get-attributes.c
+- testsuites/validation/tc-intr-handler-iterate.c
 - testsuites/validation/tc-intr-is-pending.c
 - testsuites/validation/tc-intr-raise.c
 - testsuites/validation/tc-intr-raise-on.c