This broke the GreenDragon build, due to the following error while running
TestImportBuiltinFileID:
```
Ignored/unknown shouldn't get here
UNREACHABLE executed at tools/clang/include/clang/Sema/AttrSpellingListIndex.inc:13!
```
See http://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/24213/
This reverts commit 73c6beb2f7053fe8b5150072c2b5cd930de38a22.
This reverts https://reviews.llvm.org/D89318
During the import of attributes we forgot to set the spelling list
index. This caused a segfault when we wanted to traverse the AST
(e.g. by the dump() method).
Differential Revision: https://reviews.llvm.org/D89318
During the import of FormatAttrs we forgot to import the type (e.g
`__scanf__`) of the attribute. This caused a segfault when we wanted to
traverse the AST (e.g. by the dump() method).
Differential Revision: https://reviews.llvm.org/D89319
