ALWAYS_SPLIT seems necessary for ZFP

[FrancescAlted]

At least these tests:

FAILED tests/ndarray/test_lossy.py::test_lossy[shape1-float64-cparams1-None-False] - RuntimeError: Error while creating the NDArray
FAILED tests/ndarray/test_lossy.py::test_lossy[shape3-float32-cparams3-lossy.b2nd-False] - RuntimeError: Error while creating the NDArray

fail if "splitmode" is set toAUTO_SPLIT, which is the new default after this discussion.

Perhaps this is due to the design of the test, but while we can investigate more, they are set explicitly in the test to ALWAYS_SPLIT.