_Atomic along with restrict is considered an error

I believe that in this code:

```c
static int * restrict a36;
static int * _Atomic b36;
static int * _Atomic restrict i36; /* error here */
```

both '_Atomic' and 'restrict' are valid type qualifiers.
Yet, the third line is considered an error.

Reproduce the reported diagnostic with the C snippet in the issue. Start by tracing how Clang parses and validates the combined _Atomic and restrict qualifiers, then identify the relevant compiler test location from that diagnostic path. Done means the valid qualifier combination is accepted and a regression test covers the example.

Written by the indexing model from the issue text.