[Rust] validation of offsets buffer is incorrect for `List<T>`

[asfimport]

Reporter: Paddy Horan / @paddyhoran
Assignee: Paddy Horan / @paddyhoran

PRs and other links:

• GitHub Pull Request #2877

_{Note: This issue was originally created as ARROW-3658. Please see the migration documentation for further details.}

[asfimport]

Uwe Korn / @xhochy:
Issue resolved by pull request 2877
#2877