[llvm] [PDB] Fix missing `consumeError` which raise error with asserts enabled (PR #116480)

[Romain Thomas via llvm-commits]

romainthomas wrote:

I can't share the PDB that triggers this code path but the changes are pretty conservative and idiomatic with other `consumeError` used in this source file.

https://github.com/llvm/llvm-project/pull/116480