- before returning a `"simplify"` response, check if any constrains are
`false` and return `#Bottom` in that case
- when simplifying rewriting results, prune branches if there's a
literal `false`
- this triggers the change in the `test-vacuous` integration test, where
the original state is now returned.
[simplifyP](https://github.com/runtimeverification/haskell-backend/blob/booster-bottom-on-false-constaint/booster/library/Booster/Pattern/Rewrite.hs#L1029)
now returns `Nothing` for the result and thus we get to return
`RewriteTrivial` from `performRewrite`
- note that the outdated responses for this integration tests actually
had a literal `false` as one of the constraints.