[clang] Implement `-dump-deserialized-declaration-ranges` flag. (PR #133910)

[Viktoriia Bakalova via cfe-commits]

VitaNuo wrote:

> > > Another thought that crossed my mind is that we are actually heavily optimizing for minimization, but use a name that creates an impression we might care about something else. I don't have great ideas there, but maybe -dump-minimization-hints would be appropriate? Any thoughts on this?
> > 
> > 
> > TBH I would prefer not to do that. Although we're doing this for minimization, there's nothing particular about the deserialized ranges or the JSON format that we produce that limits its use to minimization. If someone else find this useful, I would only welcome that. So in this sense, I'd prefer not to have a very specific name.
> 
> I am in favor of using `-dump-minimization-hints` to scope it down and avoid Hyrum's law. If we want to be more descriptive, we could have this as a `CommaJoined` flag, eg. `-dump-minimization-hints=deserialized-decl-ranges,some-other-future-hint,all`.

Thanks. I will rename the flag in that case. PTAL.

https://github.com/llvm/llvm-project/pull/133910