turnip: Skip rather than invalidate LRZ on gl_FragDepth writes.

turnip: Skip rather than invalidate LRZ on gl_FragDepth writes.

As long as the direction is still compatible, if we skip the LRZ use and
updates for this draw, then we can keep using LRZ later in the scene, as
whatever gl_FragDepth will get written by the shader later will still have
to move the depth in the right direction.

Similarly, the no_earlyz flag that contributes to DISABLE_LRZ just wants
to make sure we don't kill fragments before dispatch, not change what Z
eventually lands.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18606>