Right now neither `sat` nor `sim` have support for the `$check` cell.
For formal verification it is a good idea to always run either
async2sync or clk2fflogic which will (in a future commit) lower `$check`
to `$assert`, etc.
While `sim` should eventually support `$check` directly, using
`async2sync` is ok for the current tests that use `sim`, so this commit
also runs `async2sync` before running sim on designs containing
assertions.
- Root AST_PREFIX nodes are now subject to genblk expansion to allow
them to refer to a locally-visible generate block
- Part selects on AST_PREFIX member leafs can now refer to generate
block items (previously would not resolve and raise an error)
- Add source location information to AST_PREFIX nodes