[llvm-branch-commits] [CI] Make premerge advisor exit with code 0 if failures are explained (PR #172394)

[Aiden Grossman via llvm-branch-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/172394

This will mark the CI as green if the premerge advisor is able to
explain all of the failures. We have seen many false negatives (failures
not explained that should be), but no false positives (failures
explained that should not be) so far.