[clang] [Clang] remove qualifiers in getCanonicalTypeUnqualified (PR #170271)

[Corentin Jabot via cfe-commits]

cor3ntin wrote:

@AaronBallman right, it's a conformance fix to a recently added built-in. I would hope no one relies on the old behavior nor should we keep the old behavior around. 

https://github.com/llvm/llvm-project/pull/170271