MSVC Xbox 360 jump table relocations are wrong on objdiff

[rjkiv]

Jump table lis/addi relocs on MSVC X360 are branching to inst 0, instead of the first inst after the bctr.

I was able to confirm this is an issue with objdiff and not jeff, by verifying the .obj and the .s files' output and viewing the correct relocs on their ends:

The correct relocation is there in the .s/.obj, objdiff just does not currently use it.

[rjkiv]

https://github.com/encounter/objdiff/blob/main/objdiff-core/src/arch/ppc/mod.rs#L241

The current working theory is that this line is responsible - it hard sets the addend to 0, when it should be using the addend that's part of the reloc. However, attempts to replace it with reloc.addend() have not been successful.