[clang] [clang][AST] Fix printing `TagDecl`s. (PR #69971)

[Richard Smith via cfe-commits]

zygoloid wrote:

> At this point we either ignore the implicitly generated `TagDecl`, or we can tweak the attribute printing, so that they are printed even if we only print the declaration, though when I tried that 10 test cases failed, so I'm not sure we want to pursue that solution.

I think we should always print attributes, but only print the ones that are not inherited (that is, the ones that are written on *that* declaration).

https://github.com/llvm/llvm-project/pull/69971