Handle resetting atrac play position more correctly when adding data

[unknownbrackets]

This ensures we instruct the game to put the data in the same places as the PSP would ask it to. Also, these places make sense. High level:

• For a fully loaded song: tell the game not to add anything. Makes sense.
• For a partially loaded song (intended to fit entirely in PSP RAM): tell the game to add sequentially to the end of the existing buffer.
• For a streaming song: tell the game to add the new data to the start of the buffer, with a bit of leading data. This implies to me the decoder needs to "warm" with a few frames. Also give a minimal size to load for decoding.

This also improves validation. Now both tests pass from hrydgard/pspautotests#177.

Additionally, this fixes music looping in Trails in the Sky SC. The reason is that it first seeks to 0, adding data, and then seeks later into the song. Previously, this would corrupt the data stream because it would add the initial bytes incorrectly. I strongly suspect this is the same problem the games in #8147 have.

-[Unknown]

[daniel229]

Fixed #8147

[daniel229]

Breaks kurohyo 2

27:20:721 sgx-psp-at3- I[ME]: HW\MediaEngine.cpp:87 FF: Invalid start bit!
27:20:721 sgx-psp-at3- E[ME]: HLE\sceAtrac.cpp:444 avcodec_decode_audio4: Error decoding audio -1094995529 / bebbb1b7
27:20:729 sgx-psp-at3- I[ME]: HLE\sceAtrac.cpp:1437 sceAtracReleaseAtracID(0)

[daniel229]

I can't reproduce the second time,weird.