[clang] Sort attributes according to source position before printing (PR #162556)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> Ah, whew, so it IS just a handful that are inserted incorrectly! That is good to know. The `AsmLabelAttr` being a 'special' thing there is a little frustrating... however, does its order ever matter? I wouldn't expect so? So it at least shouldn't cause any problems, right?

Yeah, the order matters because we have to do custom parsing for `AsmLabelAttr`. This would apply to any attribute which is using a custom keyword or custom parsing rules, I suspect.

https://github.com/llvm/llvm-project/pull/162556