Automatic merge from submit-queue
rkt: Wrap exec errors as utilexec.ExitError
This is needed by the exec prober to distinguish error types and exit
codes correctly. Without this, the exec prober used for liveness probes
doesn't identify errors correctly and restarts aren't triggered. Fixes#26456
An alternative, and preferable solution would be to use utilexec
everywhere, but that change is much more involved and should come at a
later date. Unfortunately, until that change is made, writing tests for
this is quite difficult.
cc @yifan-gu @sjpotter
8e091e254f