[mlir][Vector] Add folding of vector transfers from/into tensor producing ops.

[mlir][Vector] Add folding of vector transfers from/into tensor producing ops.

Add a folder to rewrite a sequence such as:

```
   %t1 = ...
   %v = vector.transfer_read %t0[%c0...], {masked = [false...]} :
     tensor<static_sizesxf32>, vector<static_sizesxf32>
  %t2 = vector.transfer_write %v, %t1[%c0...] {masked = [false...]} :
     vector<static_sizesxf32>, tensor<static_sizesxf32>
```

into:

```
   %t0
```

The producer of t1 may or may not be DCE'd depending on whether it is a
block argument or has side effects.

Differential revision: https://reviews.llvm.org/D97934