Core: Run before and after hooks with module context

[raycohen]

The before and after hooks run once per module as long as there is at least one test in the module. Using environment inheritance allows us to use the module context in those hooks, which allows reading the expected changes to the context from a before hook inside nested modules.

This is a breaking change and would need to be part of a major version bump.

Fixes #1328. Ref #869.