[clang] [libcxx] [llvm] Reapply "[Clang] Implement resolution for CWG1835 (#92957)" (PR #98547)

[Krystian Stasiowski via llvm-commits]

sdkrystian wrote:

> Another option would be to apply the resolution to all modes, but recover and issue a warning instead of an error. How feasible would that be?

@mizvekov Without unannotated tentative parsing (to be _properly_ introduced by #96364), issuing a warning is infeasible. Either way, by the time we detect the error we could be who knows how deep into the second operand of a `>` operator.

https://github.com/llvm/llvm-project/pull/98547