[clang] Switch builtin strings to use string tables (PR #118734)

[Chandler Carruth via cfe-commits]

chandlerc wrote:

Discussion thread about the MSVC version change: https://discourse.llvm.org/t/rfc-raising-minimum-msvc-version-by-one-patch-release/83490

https://github.com/llvm/llvm-project/pull/118734