[compiler-rt] [MSan] Fix wrong unpoison size in SignalAction (PR #144071)

[Kunqiu Chen via llvm-commits]

Camsyn wrote:

> lgtm. as a sidenote, pressing this icon helps bring the change back to the reviewer's attention
> 
> ![image](https://private-user-images.githubusercontent.com/19826/456266141-6967f736-554e-4e6d-9b05-a3710fa73583.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.QKL7M4vky7-GOgpoEGiY_1534rGlWOnQfAmRmyJRxTY)

@fmayer That icon seems to require a formal review (approve/request for change) from the reviewer before it appears (because that icon does not appear in my other open PR, where the reviewer also did not give a formal review, but left a comment).

It seems that in this case, I can only ping through @?

Anyway, thank you for the kind reminder.

https://github.com/llvm/llvm-project/pull/144071