[non-BE] [split-non-BE] [allow-regression] basop-2406-stereo-decoder-highband-missing-attenuated

• Related issues: #2406 (closed)
• Requested reviewers: @vaclav

Reason why this change is needed

• There is still an issue in the BASOP decoder compared to floating-point: The highband (6.4-8kHz) is apparently missing or strongly attenuated. The problem was occurring in inactive content at 16kHz.

Description of the change

• The mean gain is added to the 2 band covering the 6.4-8kHz
• brings BASOP in sync with FLP

Affected operating points

• Bitstream IO

• all modes using the inactive coder_type at 24.4 or 32 kbps might be affected

• Impact on quality is low

  close #2406 (closed)