BASOP and instrumentation updates in lib_dec

• EVS 26.444 BE test passes.
• decoder pytests:
  MLD scores:
  Original inputs: 562 failed, 374 skipped
  MLD > 10: 6
  MLD > 5 : 63
  MLD < 5 : 493
  +10dB inputs: 562 failed, 374 skipped
  MLD > 10: 92
  MLD > 5 : 182
  MLD < 5 : 288
  -10dB inputs: 562 failed, 374 skipped
  MLD > 10: 2
  MLD > 5 : 12
  MLD < 5 : 548
• encoder pytests results:
  MLD scores:
  Original inputs: 562 tests:
  MLD > 10: 18
  MLD > 5 : 67
  MLD < 5 : 477
  +10dB inputs: 562 tests:
  MLD > 10: 68
  MLD > 5 : 122
  MLD < 5 : 372
  -10dB inputs: 562 tests:
  MLD > 10: 5
  MLD > 5 : 24
  MLD < 5 : 533