[llvm] [xray] Fix stack alignment for custom event calls. (PR #89360)

[Ricky Zhou via llvm-commits]

rickyz wrote:

@llvm/pr-subscribers-xray since the paths at https://github.com/orgs/llvm/teams/pr-subscribers-xray don't seem to match this PR.

https://github.com/llvm/llvm-project/pull/89360