[clang-tools-extra] Add refactoring tool to convert between ternary (?:) expressions and equivalent if/else statements (PR #166822)

[via cfe-commits]

EugeneZelenko wrote:

`modernize` module is about upgrading to features of new C++/C standards. Ternary and conditional operator are part of original C. Choice between them is clearly question of code style.

https://github.com/llvm/llvm-project/pull/166822