[Wilds] Fix some minor classtree issues identified by unit tests

Summary: Ref T13098. I eventually got unit tests sort-of-almost running and they caught these two issues. Since the tests don't get very far with these classtree problems, just fix them up now so when arc unit actually runs later on it can meaningfully run tests.

Test Plan: Ran arc unit, after other changes let it run, and saw fewer "class doesn't implement every abstract method" issues.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13098

Differential Revision: https://secure.phabricator.com/D19708