Fix loading gzip files in stage2

[InvoxiPlayGames]

Switching to using puff in 48244cc broke loading gzip compressed files in stage2 due to an oversight where puff expects raw data, while the buffer being passed contains the gzip header. Stage1 did this correctly.

This just brings over some of the corrected logic from stage1 into stage2's file loader. This also cleans out some leftover commented code and displays useful data like the size of decompressed data and the error code returned by puff, if any.

[Locoabordo]

InvoxiPlayGames:gzip_load_fix