[clang] [llvm] Revert "Enable unnecessary-virtual-specifier by default" (PR #134105)

[Hans Wennborg via cfe-commits]

zmodem wrote:

> This causes the whole libc++ CI to fail, since we're not building against a compiler built from current trunk.

Can you provide an example, such as a link to a failing build, or an explanation of the failure? I found https://buildkite.com/llvm-project/libcxx-ci/builds?created_from=2025-04-01&created_to=2025-04-01 but didn't see any failures related to Devon's change there.

https://github.com/llvm/llvm-project/pull/134105