Clean up recursion checks

[classilla]

https://bugzilla.mozilla.org/show_bug.cgi?id=1342721
https://bugzilla.mozilla.org/show_bug.cgi?id=1342439

These show up in profiles, so they would be a good target for work. For FPR1, let's start with https://bug1342439.bmoattachments.org/attachment.cgi?id=8840922

[classilla]

Decided to take 1342721 instead, since it's less invasive.