fdre-a3xx: properly handle rptN and attr ranges

If an instruction repeat flag pushes the register value into the next
vec4 (or group of four scalars, depending on how you look at it), or if
@attribute range ends in the next vec4, we need to account for this
properly when we track the register usage.
fdre-a3xx: add lolscat test

Make depth buffer work, and fix some things w/ clear vs blend state,
etc.