[inferbo] Do not store dummy idents into stack
[inferbo] Do not store dummy idents into stack

Summary:
:
Do not store dummy `_` into the stack.
This makes debugging a lot easier

Reviewed By: skcho

Differential Revision: D5275941

fbshipit-source-id: ce329a5

jvillard/infer,jvillard/infer,blzq/infer,jvillard/infer,facebook/infer,ropas/infer,blzq/infer,ropas/infer,ropas/infer,facebook/infer,jvillard/infer,ropas/infer,facebook/infer,jvillard/infer,facebook/infer,ropas/infer,facebook/infer,blzq/infer,blzq/infer,ropas/infer,jvillard/infer,facebook/infer,blzq/infer,blzq/infer,jvillard/infer,facebook/infer