[clang] [clang][AST] Fix positioning of preserve cconv attributes in TypePrinter (PR #147285)

[via cfe-commits]

Sirraide wrote:

AST printing has historically only really been best-effort, i.e. we don’t actually care too much that the code that we print actually compiles, but I think @AaronBallman has a more-informed opinion on that as I recall.

https://github.com/llvm/llvm-project/pull/147285