align_to and align_to_mut contract and harnesses

[AlexLB99]

Towards solving #19

This PR adds harnesses and contracts for align_to() and align_to_mut(). For the contract for align_to_mut(), we're using a wrapper and writing a contract for that instead, due to model-checking/kani#3764.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

[tautschnig]

Thank you! We should have a fix for the Kani issue with model-checking/kani#4151 really soon, so I'd love to hold off on this one for about a week so that we can get the Kani fix merged and have this repository use the updated Kani version.

[tautschnig]

Thank you! We should have a fix for the Kani issue with model-checking/kani#4151 really soon, so I'd love to hold off on this one for about a week so that we can get the Kani fix merged and have this repository use the updated Kani version.

@AlexLB99 We now have the Kani fix merged and the version of Kani that this repository uses includes this fix. Could you please adjust your implementation so as not to use a workaround anymore?

[AlexLB99]

Thank you! We should have a fix for the Kani issue with model-checking/kani#4151 really soon, so I'd love to hold off on this one for about a week so that we can get the Kani fix merged and have this repository use the updated Kani version.

@AlexLB99 We now have the Kani fix merged and the version of Kani that this repository uses includes this fix. Could you please adjust your implementation so as not to use a workaround anymore?

Thanks for letting me know -- I've added a new commit that removes the workaround (so now align_to_mut itself has a contract)

[tautschnig]

Please review what changes are actually intended.

[AlexLB99]

Yes those were definitely the result of a mis-merge; it should be fixed now