Adds tests with scalable vectors for the Vector-To-LLVM conversion pass. Covers the following Ops: * `vector.load`, * `vector.store`. In addition: * For consistency with other tests, renamed test function names (e.g. `@vector_load_op_nontemporal` -> `vector_load_nontemporal`) * Moved `@vector_load_0d` near other test for `vector.load` (as opposed to next to `@vector_store_0d`).