arrow

MINOR: [C++] Add check for result of MakeExecNode (#13849)

ARROW-16894 added benchmarks for asof join node. This PR adds a call to `ASSERT_OK` to satisfy the warning that the `Result` returned by `MakeExecNode` was not checked.

Authored-by: Aldrin M <octalene.dev@pm.me>
Signed-off-by: Weston Pace <weston.pace@gmail.com>