[mlir][linalg] Add an e2e test for linalg.matmul_transpose_a to ArmSME (#71644)

This patch adds an integration test demonstrating the first e2e example
lowering a linalg.matmul to SME via vector.outerproduct.

The test uses a 'linalg.matmul_transpose_a' rather than 'linalg.matmul'
since the latter emits a 'vector.transfer_read' with a vector type of
'vector<[4]x1xf32>' that can't be currently lowered via generic (SVE)
path, since it has leading scalable dim.