Add operations for easy arithmetic that panics on overflow

[RalfJung]

See the ACP at rust-lang/libs-team#270. The ACP has been seconded so it seems like the next step is implementation. This should be fairly easy to do, just following the patterns established by the existing methods and adjusting them to panic on overflow.

[rmehri01]

@rustbot claim

[mintsuku]

Is this issue still persistent/available to pick up?

[RalfJung]

#116090 is implementing this, it's just waiting for review.

[eduardosm]

With #116090 merged and #118260 as tracking issue, this could be closed.

[RalfJung]

Great :)