In libc++ most of the names are not conforming to the llvm style. Removing the readability-identifier-naming check removes almost all clang-tidy warnings. For example in `<string>` the warning count goes from 1001 warnings down to 7.
Reviewed By: #libc, Mordante, ldionne
Spies: Mordante, Quuxplusone, aheejin, libcxx-commits, carlosgalvezp
Differential Revision: https://reviews.llvm.org/D113849
Nikolas Klauser