Fix depth texture being incorrectly affected by swap table

Software: Remove alpha=1 blending special-case

This was added in #10394 for both the hardware and software backends to work around an issue with Mario Kart Wii, Fortune Street, and Baten Kaitos. However, it seems like the software renderer handles blending well enough that we don't need this (and in any case, it's easy to change blending in the software renderer).

Some experimentation with #11387 (not pushed) showed that the software renderer's logic would also produce correct results on the hardware backends with this hack removed, but would require fbfetch (currently); if a better solution is found the hack can also be removed from the hardware backends.

Texture dumping can already be done using VideoCommon's system (and in fact the same setting already enabled *both* of these). Dumping objects/TEV stages/texture fetches doesn't currently have an equivalent, but could be added to the FIFO player instead.

It stores both the konst selection value for alpha and color channels (for two tev stages per ksel), and half of a swap table row (there are 4 total swap tables, which can be used for swizzling the rasterized color and the texture color, and indices selecting which tables to use are stored per tev stage in the alpha combiner).  Since these are indexed very differently, the old code was hard to follow.