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

[Pranav Kant via cfe-commits]

pranavk wrote:

Could we perhaps put this behind a flag to help with the transition?

Some cases can already be silenced with -Wno-missing-dependent-template-keyword but cases like above in absl are hard errors and there are no workarounds. 

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