* Update preview1 to trap on misaligned pointers
Previously Wasmtime would return `EINVAL` to a guest but the upstream
documentation indicates that misaligned pointers should trap, so this
commit updates the alignment error to get converted into a trap rather
than than being returned to the guest.
* Change OOB errors to traps too
* Update preview2's implementation of preview1
* Handle some more errors
Alex Crichton