[clang] [clang][TypePrinter] Replace AppendScope with printNestedNameSpecifier (PR #168534)

[Aiden Grossman via cfe-commits]

boomanaiden154 wrote:

It seems like this caused a regression in at least one case.

https://godbolt.org/z/bzY1qbboc

For a simple example:
```c++
typedef union {
  struct {
    unsigned int a : 1;
    unsigned int b : 1;
    unsigned int c : 1;
    unsigned int d : 2;
    unsigned int e : 1;
    unsigned int f : 1;
    unsigned int g : 1;
  };
  unsigned char val;
} session_u;

session_u bar;
```

We were getting the following (from `-fdump-record-layouts`):
```
         0 | struct session_u::(anonymous at <source>:2:3)
     0:0-0 |   unsigned int a
     0:1-1 |   unsigned int b
     0:2-2 |   unsigned int c
     0:3-4 |   unsigned int d
     0:5-5 |   unsigned int e
     0:6-6 |   unsigned int f
     0:7-7 |   unsigned int g
           | [sizeof=4, dsize=4, align=4,
           |  nvsize=4, nvalign=4]
```

But now we are getting the following:
```
*** Dumping AST Record Layout
         0 | struct (anonymous union)::(anonymous at <source>:2:3)
     0:0-0 |   unsigned int a
     0:1-1 |   unsigned int b
     0:2-2 |   unsigned int c
     0:3-4 |   unsigned int d
     0:5-5 |   unsigned int e
     0:6-6 |   unsigned int f
     0:7-7 |   unsigned int g
           | [sizeof=4, dsize=4, align=4,
           |  nvsize=4, nvalign=4]
```

Where the union is now listed as anonymous despite it being given a name.

https://github.com/llvm/llvm-project/pull/168534