These tests basically were integration tests as unit tests, checking too many passes at once to be useful, and brittle to any changes. This patch moves (non-duplicated) tests to `vector-to-arm-sme.mlir` (which only tests `-convert-vector-to-arm-sme`). The lowering after that e.g. `ArmSME -> SCF` and `ArmSME -> LLVM` already have their own set of tests covering these cases.