Add more tests for ctr_logging.c

[jankaluza]

This commit adds tests for:

• the --log-label option.
• the --log-tag option.
• the parsing of journald priority level.
• the partial message in both journald and k8s-file.
• the log rotation using the ctl command.

[jankaluza]

This depends on #605. I will rebase it once #605 is done.

[jankaluza]

@jnovy , this is ready for review now.

[jnovy]

Could you remove:

@test "ctrl: rotate logs" {
    start_conmon_with_default_args --log-path "k8s-file:$LOG_PATH" -t
    wait_for_runtime_status "$CTR_ID" running

    # Remove the log.
    rm -f $LOG_PATH
    # The control message should reopen/recreate it.
    echo "2 1 1" > ${CTL_PATH}

    start_conmon_with_default_args \
        --log-path "k8s-file:$LOG_PATH.exec" \
        --exec \
        --exec-process-spec "${BUNDLE_PATH}/process.json"

    wait_for_runtime_status "$CTR_ID" stopped

    # Check that the log exists now.
    assert_file_exists "$LOG_PATH"
    run cat "$LOG_PATH"
    # No terminal resize
    assert "${output}" =~ "standard input"
}

As you r new test tests the same thing more throughly?

[jankaluza]

This test actually tests that you can rotate logs using the control message. This is different scenario than the ones in the 03-k8s-log-rotation.bats.