core: Remove unused CiTrace source files

These source files have been unused for the entire lifecycle of the
project. They're a hold-over from Citra and only add to the build time
of the project, so they can be removed.

There's also likely no way this would ever work in yuzu in its current
form without revamping quite a bit of it, given how different the GPU on
the Switch is compared to the 3DS.