Fix regressions introduced by #1362

It's not actually incorrect to retire an instruction while in WFI-mode.
The assertion was enforcing a particular uarch behavior, not the spec.

Make CLINT optional

Misc. utility improvements and generalizations

Bump riscv-tools to pick up lots of Debug-related changes.

Adding an ugly hack to get the current module during elaboration.

Debug: work around param case class serialization limitation

This allows D$/TLB misses to be suppressed from later in the pipeline.

Initial commit of SBA Debug feature