[mlir][linalg] Add an e2e test for linalg.matmul to ArmSME (#72144)

This patch adds an integration test lowering a linalg.matmul to SME via
vector.outerproduct.

It's similar to the linalg.matmul_transpose_a e2e test added recently in
as well as vector transpose canonicalizations, to lower the following
sequence (taken from the inner loop):
```
  %subview = memref.subview %arg0[%arg3, %arg5] [%2, 1] [1, 1] :
    memref<?x?xf32, strided<[?, ?], offset: ?>> to memref<?x1xf32, strided<[?, ?], offset: ?>>
  %mask = vector.create_mask %2, %c1 : vector<[4]x1xi1>
  %0 = vector.transfer_read %subview[%c0, %c0], %pad, %mask {in_bounds = [true, true]} :
    memref<?x1xf32, strided<[?, ?], offset: ?>>, vector<[4]x1xf32>
  %1 = vector.transpose %0, [1, 0] : vector<[4]x1xf32> to vector<1x[4]xf32>
  %2 = vector.extract %1[0] : vector<[4]xf32> from vector<1x[4]xf32>
```
Rank-2 vectors with leading scalable dim can't be type converted to an
array. TransferReadDropUnitDimsPattern drops the unit dim on the
vector.transfer_read so it can be lowered via the generic path (to SVE).
The transpose canonicalizations lower the transpose to a shape_cast
which folds away.