[llvm] [SelectionDAG] Correct the implementation of m_AllOnes. (PR #90776)

[via llvm-commits]

llvmbot wrote:

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>> /cherry-pick [41466a1](https://github.com/llvm/llvm-project/commit/41466a177a95ee6ff699d190f7625f0b32922a20)
>
>What are you doing?

Error: Command failed due to missing milestone.

https://github.com/llvm/llvm-project/pull/90776