freedreno/ir3: add no-copy-propagate fallback step

freedreno/ir3: add no-copy-propagate fallback step

Most of the things the new compiler still has trouble with basically
amount to cp stage removing too many copies.  But without the cp stage,
the shaders the new compiler produces are still better (perf and
correctness) than the old compiler.  So a simple thing to do until I
have more time to work on it is first trying falling back to new
compiler without cp, before finally falling back to old compiler.

Signed-off-by: Rob Clark <robclark@freedesktop.org>