[Analyzer] Fix for dereferece of smart pointer after branching on unknown inner pointer

Summary: Enabling warning after dereferece of smart pointer after branching on unknown inner pointer.

Reviewers: NoQ, Szelethus, vsavchenko, xazax.hun
Reviewed By: NoQ
Subscribers: martong, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D87043