[clang] [Clang] [NFC] Refactor AST visitors in Sema and the static analyser to use DRAV (PR #115144)

[Balazs Benics via cfe-commits]

steakhal wrote:

What's the benefit of using `DRAV` over `RAV`? I couldn't find the motivation in the PR summary in neither of this or the linked PR.

https://github.com/llvm/llvm-project/pull/115144