[LLDB][NativePDB] Add modifiers to modified type name (#159296)

When creating LLDB types from `LF_MODIFIER` records, the type name of
the modified type was used. This didn't include the modifiers
(`const`/`volatile`/`__unaligned`). With this PR, they're included.

The DIA plugin had a test for this. That test also assumed that function
types had a name. I removed that check here, because function/procedure
types themselves in PDB don't have a name:

```
  0x1015 | LF_ARGLIST [size = 20, hash = 0xBCB6]
           0x0074 (int): `int`
           0x1013: `int* __restrict`
           0x1014: `int& __restrict`
  0x1016 | LF_PROCEDURE [size = 16, hash = 0x3F611]
           return type = 0x0003 (void), # args = 3, param list = 0x1015
           calling conv = cdecl, options = None
```

I assume DIA gets the name from the function symbol itself. In the
native plugin, that name isn't included and multiple functions with the
same signature will reuse one type, whereas DIA would create a new type
for each function. The
[Shell/SymbolFile/PDB/func-symbols.test](https://github.com/llvm/llvm-project/blob/b29c7ded31d81ca47aed0157c543c8b6a0f5866c/lldb/test/Shell/SymbolFile/PDB/func-symbols.test)
also relies on this.