Missed a null-ptr check in previous PR for Debuginfod testing (#86292)

@GeorgeHuyubo noticed an unchecked shared pointer result in
https://github.com/llvm/llvm-project/pull/85693/. This is the fix for
that issue.

Co-authored-by: Kevin Frei <freik@meta.com>
GitOrigin-RevId: b1575f9082071702bd6aaa2600ce9fe011a091e9
1 file changed