[MLIR] Fix mishandling of canonicalization in MLIR constant handler.
[MLIR] Fix mishandling of canonicalization in MLIR constant handler.

(This probably needs a test, but I'd rather work on removing canonicalization from this level of the software stack.)

PiperOrigin-RevId: 414168031

google/jax,google/jax,google/jax,google/jax