[pulse] Check new_eq of type EqZero
[pulse] Check new_eq of type EqZero

Summary:
The previous sanity check for [PulseFormula.new_eqs] was too lenient: it
ignored EqZero completely. Now we take it into account.

Reviewed By: jvillard

Differential Revision: D40636934

fbshipit-source-id: da47fe6bcb7f26c08b2fcfa2e4affc148ccbc4dc

facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer