…liance#11242)

This commit fixes an accidental regression from bytecodealliance#11097 where a
`select_spectre_guard` with a boolean condition that and'd two CCs
together would fail to lower and cause a panic during lowering. This was
reachable when explicit bounds checks are enabled from wasm, for
example. The fix here is to handle the `And` condition in the same way
that lowering `select` does which is to model that as it flows into the
select helper.