[clang] [Clang] Add NormalizedConstraint::dump() (PR #210498)

[Younan Zhang via cfe-commits]

zyn0217 wrote:

> As far as the format itself, there are a couple that are mildly awkward (an extra space after T() and before the comma in atomic constraint), but nothing I'm really concerned about.

That might be something buggy inside our TextNodeDumper, AFAIK that comma expression is itself an atomic expression and thus it's printed out through `Expr::print()`

https://github.com/llvm/llvm-project/pull/210498