These are only used in this translation unit.

These were also missing the shifted register case.

Loader: Keep a reference to the file and pass it to the correct AppLoader, instead of loading it multiple times.

Display transfers with the horizontal downscaling flag were calculating
the wrong output size, causing them to write double the amount of data
intended. It is likely that this was perceived as correct due to a
separate bug in calculating source indices which caused the image to be
padded unless the previous bug was present.

This fixes both issues, correcting flickering issues in 3dscraft,
blargSnes and more (caused by the transfer overwriting the back buffer
which followed) as well as potentially fixing other crashes.

The code was previously appending the interrupt to after the end of the
buffer, instead of at the end.

It appears this is a mistake, since the sub-screen has no right
framebuffer.

Hardware testing determined that the GSP processes shared memory
framebuffer update info even when no memory transfer or filling GX
commands are used. They are now updated on every interrupt, which isn't
confirmed correct but matches hardware behaviour more closely.

This also reverts the hack introduced in #404. It made a few games
behave better, but I believe it's incorrect and also breaks other games.