[clang] [clang][ASTImporter] Add import of node 'FileScopeAsmDecl' (PR #193244)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

I found one questionable part, otherwise LGTM (although I'm still not an expert of this area).

https://github.com/llvm/llvm-project/pull/193244