[clang] [Clang] Reapply CWG2369 "Ordering between constraints and substitution" (PR #122423)

[Younan Zhang via cfe-commits]

zyn0217 wrote:

@mysterymath @zmodem Can you both test this patch on Windows to confirm if it resolves issues you've reported? We'd greatly appreciate it!


https://github.com/llvm/llvm-project/pull/122423