[clang] [llvm] [clang][SPIRV] Set program address space for Intel-flavored SPIR-V (PR #135251)

[Nick Sarnie via cfe-commits]

sarnex wrote:

@Naghasan Attempted to implement your feedback in the latest commit. Can you take a look?

Also can you confirm that IR like 

```
call spir_func noundef addrspace(9) foo()
```

is correct if the extension is enabled? 

https://github.com/llvm/llvm-project/pull/135251