[llvm] [RemoveDIs] Fix asan-identified leak in unittest (PR #106723)

[via llvm-commits]

llvmbot wrote:

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Failed to cherry-pick: 7ffe67c17c524c2d3056c0721a33c7012dce3061

https://github.com/llvm/llvm-project/actions/runs/10633781920

Please manually backport the fix and push it to your github fork.  Once this is done, please create a [pull request](https://github.com/llvm/llvm-project/compare)

https://github.com/llvm/llvm-project/pull/106723