Update tests to eliminate public declarations.
Update tests to eliminate public declarations.

- This is in prep for a proposed MLIR change to disallow public declarations.
  https://llvm.discourse.group/t/rfc-symbol-definition-declaration-x-visibility-checks/2140

PiperOrigin-RevId: 342286831

google-research/structured-additive-IR,google-research/structured-additive-IR