fix #33081: acoustic bass channel info

I don't get it. 43 and 44 are tremolo and pizz strings no? Why associating them to arco and tremolo?

There are other Bass technics in MIDI 
32 Acoustic Bass
33 Electric Bass (finger)
34 Electric Bass (pick)
35 Fretless Bass
36 Slap Bass 1
37 Slap Bass 2