[clang] [clang-tools-extra] Reland [clang][Sema, Lex, Parse] Preprocessor embed in C and C++ (PR #95802)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman approved this pull request.

Leak fix LGTM, I think it's ready to re-land and try again.

https://github.com/llvm/llvm-project/pull/95802