v3d: Always emit a TF disable at the start of drawing on V3D 4.x.

v3d: Always emit a TF disable at the start of drawing on V3D 4.x.

The HW's FLUSH_ALL_STATE is not validated, so we probably shouldn't use
it, meaning that we need to reset state at the start.  By doing this, we
also make ourselves more resilient to another client leaving the TF state
enabled at the end of their batch (as we now do, ourselves).

However, we still need to emit a single TF disable at the end of the
frame, for SWVC5-718.