[clang-tidy] Update TransformerClangTidyCheck to use new Transformer bindings.

Summary:
Updates the relevant source files to use bindings in `clang::transformer` rather
than `clang::tooling`.

Reviewers: gribozavr

Subscribers: xazax.hun, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D69804