[Analyzer][StreamChecker] Add check for pointer escape.

Summary:
After an escaped FILE* stream handle it is not possible to make
reliable checks on it because any function call can have effect
on it.

Reviewers: Szelethus, baloghadamsoftware, martong, NoQ

Reviewed By: NoQ

Subscribers: NoQ, rnkovacs, xazax.hun, baloghadamsoftware, szepet, a.sidorin, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, gamesh411, Charusso, martong, ASDenysPetrov, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80699