[MLIR][LLVM] Remove typed pointer remnants from target tests (#71210)

This commit removes all LLVM dialect typed pointers from the target
tests. Typed pointers have been deprecated for a while now and it's
planned to soon remove them from the LLVM dialect.

Related PSA:
https://discourse.llvm.org/t/psa-removal-of-typed-pointers-from-the-llvm-dialect/74502