[clang] [clang][TableGen] Migrate clang-tblgen to use const RecordKeeper (PR #107533)

[Rahul Joshi via cfe-commits]

jurahul wrote:

This is a refactor for better const correctness in TableGen backends. Please see the discourse thread here: https://discourse.llvm.org/t/psa-planned-changes-to-tablegen-getallderiveddefinitions-api-potential-downstream-breakages/81089

https://github.com/llvm/llvm-project/pull/107533