Fix ULSCH timing measurements in RAN-gNB-nrUE-MONO-TDD-Band78-N300 and logging improvements

• in phy-test mode, forces complete decoding of PUSCH and ignores DTX
• fixes MCS shown in logs in phy-test
• ouppress MAC timing measurements in console output
• use snprintf() to avoid buffer overflows in these places:
  • print_meas_log()
  • dump_L1_meas_stats()
  • dump_L1_UE_meas_stats()
  • nrmac_stats_thread()
  • dump_mac_stats()