add test file endline.

Author: linuxlonelyeagle

mlir/test/Dialect/Affine/ops.mlir

@@ -323,4 +323,4 @@ module attributes {gpu.container_module} {
 // CHECK:             %[[VAL_3:.*]] = arith.constant 0 : index
 // CHECK:             affine.for %[[VAL_4:.*]] = %[[VAL_3]] to %[[VAL_2]] step 32 {
 // CHECK:             }
-// CHECK:             gpu.return
+// CHECK:             gpu.return