Simulator improvements

- Clean up error reporting for block vector writes
- Check mask properly for block vector writes
- When a cosimulator error occurs, abort before applying the side effect
so the state before the error can be seen.
Print all output in cosimulation mode when -v is specified
Fix a few issues

- A previous "refinement" broke saving return address on calls
- I somehow transposed wb_writeback_is_last_subcycle and wb_rollback_is_last_subcycle.
The second one is what was being used, but it is nonsensical.  Replaced with the first.