[mlir][Vector] Update patterns for flattening vector.xfer Ops (1/N) (#73522)

Updates "flatten vector" patterns to support more cases, namely Ops that
read/write vectors with leading unit dims. For example:

```mlir
%0 = vector.transfer_read %arg0[%c0, %c0, %c0, %c0] ... :
  memref<5x4x3x2xi8, strided<[24, 6, 2, 1], offset: ?>>, vector<1x1x2x2xi8>
```

Currently, the `vector.transfer_read` above would not be flattened. With
this
change, it will be rewritten as follows:
```mlir
%collapse_shape = memref.collapse_shape %arg0 [[0, 1, 2, 3]] :
  memref<5x4x3x2xi8, strided<[24, 6, 2, 1], offset: ?>>
  into memref<120xi8, strided<[1], offset: ?>>
%0 = vector.transfer_read %collapse_shape[%c0] ... :
  memref<120xi8, strided<[1], offset: ?>>, vector<4xi8>
%1 = vector.shape_cast %0 : vector<4xi8> to vector<1x1x2x2xi8>
```

`hasMatchingInnerContigousShape` is generalised and renamed as
`isContiguousSlice` to better match the updated functionality. A few
test names are updated to better highlight what case is being exercised.

0 files changed, 0 insertions, 0 deletions