Single step + interrupt might not retire any instructions
requested to merge github/fork/silabs-oysteink/silabs-oysteink_step-interrupt-noretire-pr into master
Created by: silabs-oysteink
If the core is stepping an interruptible instruction and an interrupt is asserted, the core will take the interrupt and not retire any instructions before entering debug mode. mepc/mcause is set according to the taken interrupt, and dpc will point to the first instruction of the interrupt handler.
This is in line with debug spec v1.0.0