[DT][NFC] Trim IRs for materialize_encoding_aarch64.mlir test. (iree-org#22327)

Most of hal and tensor_ext ops are dropped because they are not needed.
Only one test has such variants, which ensures that the vscale
calculation is correctly used by bindings.

It is a step towards iree-org#20825

Signed-off-by: hanhanW <[email protected]>
Signed-off-by: Philipp <[email protected]>

Author: hanhanW