Clean up art::mirror::Class::SetSuperClass.

- Move its definition from runtime/mirror/class.h to
  runtime/mirror/class-inl.h.
- Prevent debug code from running in non-debug mode.

Test: test-art-host
Change-Id: I981cb9aa5c59c75c6a1c4d2145185cf8b147e2db
2 files changed