Merge branch 'dmesg/tests' of https://github.com/t-8ch/util-linux

Merge branch 'dmesg/tests' of https://github.com/t-8ch/util-linux

* 'dmesg/tests' of https://github.com/t-8ch/util-linux:
  dmesg: use symbolic defines for second conversions
  dmesg: add support for reserved and local facilities
  dmesg: (tests) validate json output
  dmesg: only write one message to json
  jsonwrt: add ul_jsonwrt_value_s_sized
  dmesg: open-code LOG_MAKEPRI
  dmesg: correctly print all supported facility names
  dmesg: error out instead of silently ignoring force_prefix