[clang-tools-extra] [clang-tidy][NFC] Enable 'readability-simplify-boolean-expr' check (PR #158706)

[Davide Cunial via cfe-commits]

capitan-davide wrote:

> You have to build llvm with assertions enabled/in debug mode for that to happen (most LLVM docs will use Release by default since debug is a large build).

What I mean is that currently, no assertion expression is getting refactored as it's probably not too complex 

https://github.com/llvm/llvm-project/pull/158706