sceAudioOut2PortCreate threw for 12-channel ports, which PPSA26344
creates as its two 7.1.4 float beds (data format 0xc00).
Each accepted layout (1, 2, 6, 8 or 12 channels, float or int16) now
folds into the stereo mix through a coefficient table: centre, side,
back and top front channels at -3 dB, top back channels at -6 dB into
the front, LFE dropped. Zero coefficients are skipped, so NaN or Inf on
a dropped channel does not reach the mix. Ports of 3, 4, 5 or 7
channels, which were mixed as L/R, now throw, as do other counts and
formats with any of bits 12-31 set. The assumed format fields,
channel order and coefficients are listed in TechnicalDebt.
The new audio_out2_port_layouts test checks each layout's fold, float
and int16, and the formats that throw.