[clang-tidy] Added pointer types to clang-tidy readability-identifier-naming check.

Summary:

Option to check for different naming conventions on the following types:

  - GlobalConstantPointer
  - GlobalPointer
  - LocalConstantPointer
  - LocalPointer
  - PointerParameter
  - ConstantPointerParameter

When not specified, the conventions for the non pointer types will be applied (GlobalConstant, GlobalVariable, LocalConstant, ...).

Patch by ffigueras!

Reviewers: alexfh, kbobyrev

Reviewed By: alexfh

Subscribers: xazax.hun, cfe-commits

Differential Revision: https://reviews.llvm.org/D52882

llvm-svn: 343788