The importer test files should match the corresponding test files elsewhere and should be straight-forward. We review them by comparing them against existing reviewed files and pointing out the differences, if any.
The noder files are related to @mdempsky 's work on the unified IR and need to be reviewed in full. This is planned to happen by the end of October (before the freeze).
@aclements My understanding is that @mdempsky is working on getting all the remaining prerequisites in place (such as a compiler-matching importer for go/types, which I reviewed yesterday). We will review these files soon.