adb_shell: handle zero stdout on error
adb_shell: handle zero stdout on error

It looks like on recent systems, adb has started to correctly forward
stderr from the target device to stderr on the host (wereas in the past,
it got output to stdout on the host). This commit makes sure that
stderr gets correctly forwarded to the coller in cases where return code
checking was not enabled.

Sticklyman1936/workload-automation,Sticklyman1936/workload-automation,bjackman/workload-automation,bathepawan/workload-automation,Sticklyman1936/workload-automation,Sticklyman1936/workload-automation,jimboatarm/workload-automation,jimboatarm/workload-automation,bathepawan/workload-automation,Sticklyman1936/workload-automation,bathepawan/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,Sticklyman1936/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,bjackman/workload-automation,bathepawan/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,bathepawan/workload-automation,bathepawan/workload-automation