panfrost: Defer early-ZS classification until draw-time (Bifrost onwards)

Bifrost (and Valhall) separate early-ZS configuration into two fields: when does
the depth/stencil buffer update happen? and when are pixels killed by the
depth/stencil tests? The driver separately configures these to occur early
(before the shader executes) or late (after the shader executes). Early tests
are generally more efficient, but various combinations of API state and fragment
shader properties can require late updates and/or late kills for correctness.
Determining how to configure these fields is nontrivial.

Our current implementation (on Bifrost) configures these fields at fragment
shader compile time and bakes the settings into the RSD. This is both wrong
(using early testing when late testing is required) and suboptimal (using late
testing when early testing would suffice). We need to defer this configuration
until draw time, when we know rasterizer and Z/S state.

Reclassifying at draw time (as we currently do on Valhall) would be expensive,
especially with the extra terms added in here. To cope, decouple the shader
classification from the draw-time configuration. Since there are only a few bits
of draw state involved, this implementation just calculates all possible states.
Then the draw time classification is just indexing into a lookup table.

The actual algorithm used to classify is written with correctness and clarity in
mind. Unlike the current classification algorithm (which tries to match what the
DDK does, poorly), this algorithm embeds its proofs of correctness.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Cc: mesa-stable