[pdesc][refactor] make individual modules for the pre-analyses
[pdesc][refactor] make individual modules for the pre-analyses

Summary: This clears up which code is for which pre-analysis.

Reviewed By: skcho

Differential Revision: D18573926

fbshipit-source-id: dcdefd009

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