Remove unused import

```
  error: unused import: `define_linear_ds_test`
    --> test/integration-ebpf/src/linear_data_structures.rs:59:5
     |
  59 | use define_linear_ds_test;
     |     ^^^^^^^^^^^^^^^^^^^^^
     |
     = note: `-D unused-imports` implied by `-D warnings`
     = help: to override `-D warnings` add `#[allow(unused_imports)]`

  error: could not compile `integration-ebpf` (bin "linear_data_structures") due to 1 previous error
```

test/integration-ebpf/src/linear_data_structures.rs

@@ -56,8 +56,6 @@ macro_rules! define_linear_ds_test {
     };
 }
 
-use define_linear_ds_test;
-
 define_linear_ds_test!(Stack, TEST_STACK,
     push_fn: test_stack_push,
     pop_fn: test_stack_pop,