[llvm] [Support] Accept -no-<name> to negate cl::opt<bool> (PR #224978)

[James Henderson via llvm-commits]

https://github.com/jh7370 approved this pull request.

FWIW, the principle seems reasonable to me: --foo=0|false is an unusual and non-standard syntax. If maintaining compatibility with them is important to others, I'm okay with having support for all the variations until there's a problem with doing so.

LGTM, subject to one question.

https://github.com/llvm/llvm-project/pull/224978