update debug_test to test stepie fix

Created by: silabs-PaulZ

Updates the debug_test by writing DCSR.STEPIE and checking if interrupts are blocked or not during single step execution.

This PR should be merged after the RTL fix is merged: https://github.com/openhwgroup/cv32e40p/pull/494

Signed-off-by: Paul Zavalney paul.zavalney@silabs.com