[mlir][sparse] Add an attribute to the sort operator for stable sorting.

Reviewed By: aartbik

Differential Revision: https://reviews.llvm.org/D135181

mlir/lib/Dialect/SparseTensor/IR/SparseTensorDialect.cpp

@@ -675,6 +675,11 @@ LogicalResult SelectOp::verify() {
   return success();
 }
 
+void SortOp::build(OpBuilder &odsBuilder, OperationState &odsState, Value n,
+                   ValueRange xs, ValueRange ys) {
+  build(odsBuilder, odsState, n, xs, ys, /*stable=*/false);
+}
+
 LogicalResult SortOp::verify() {
   if (getXs().empty())
     return emitError("need at least one xs buffer.");