[analyzer] Simplify BoolAssignmentChecker

Summary:
Instead of checking the range manually, changed the checker to use assumeInclusiveRangeDual instead.

This patch was part of D28955.

Reviewers: NoQ

Reviewed By: NoQ

Subscribers: ddcc, xazax.hun, baloghadamsoftware, szepet, a.sidorin, Szelethus, donat.nagy, dkrupp, Charusso, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73062