Enable function replacements by default.

So things like Star Ocean work, and game memcpy()'s to GPU work.

This will make game start on mobile a bit slower, though.  And there could
still be bugs so leaving as an option, but seems pretty stable.  Didn't
realize it wasn't enabled by default.
Oops, fix stencil upload at non-1x resolutions.
Merge pull request #6246 from unknownbrackets/replace-funcs

Enable function replacements by default