[mlir][VectorOps] Add deinterleave operation to vector dialect

The deinterleave operation constructs two vectors from a single input
vector. Each new vector is the collection of even and odd elements
from the input, respectively. This is essentially the inverse of an
interleave operation.

Each output's size is half of the input vector's trailing dimension
for the n-D case and only dimension for 1-D cases. It is not possible
to conduct the operation on 0-D inputs or vectors where the size of
the (trailing) dimension is 1.

The operation supports scalable vectors.

Example:
```mlir
%0 = vector.deinterleave %a
           : vector<[4]xi32>     ; yields vector<[2]xi32>, vector<[2]xi32>
%1 = vector.deinterleave %b
           : vector<8xi8>        ; yields vector<4xi8>, vector<4xi8>
%2 = vector.deinterleave %c
           : vector<2x8xf32>     ; yields vector<2x4xf32>, vector<2x4xf32>
%3 = vector.deinterleave %d
           : vector<2x4x[6]xf64> ; yields vector<2x4x[3]xf64>, vector<2x4x[3]xf64>
```

mlir/include/mlir/Dialect/Vector/IR/VectorOps.td

@@ -575,14 +575,14 @@ def Vector_DeinterleaveOp :
       let summary = "constructs two vectors by deinterleaving an input vector";
       let description = [{
         The deinterleave operation constructs two vectors from a single input
-        vector. Each new vector is the collection of even and odd elements
-        from the input, respectively. This is essentially the inverse of an
-        interleave operation.
-
-        Each output's size is half of the input vector's trailing dimension
-        for the n-D case and only dimension for 1-D cases. It is not possible
-        to conduct the operation on 0-D inputs or vectors where the size of
-        the (trailing) dimension is 1.
+        vector. The first result vector contains the elements from even lanes
+        of the input, and the second contains elements from odd lanes. This is
+        the inverse of a 'vector.interleave' operation.
+
+        Each output's trailing dimension is half of the size of the input
+        vector's trailing dimension. This operation requires the input vector
+        to have a rank > 0 and an even number of elements in its trailing
+        dimension.
 
         The operation supports scalable vectors.
 

mlir/test/Dialect/Vector/invalid.mlir

@@ -1803,7 +1803,7 @@ func.func @invalid_outerproduct1(%src : memref<?xf32>) {
 
 func.func @deinterleave_zero_dim_fail(%vec : vector<f32>) {
   // expected-error @+1 {{'vector.deinterleave' 'input' must be vector of any type values, but got 'vector<f32>'}}
-  %0, %1 = vector.deinterleave %vec : vector<f32> 
+  %0, %1 = vector.deinterleave %vec : vector<f32>
   return
 }