TST: Potential inconistency between numpy and numexp
The loop variable `engine` should probably be used here instead of `self.engine`:
https://github.com/pandas-dev/pandas/blob/1367cacd7c90694a5d0563d46dd10a1e8a3ea8b3/pandas/tests/computation/test_eval.py#L466

Making this change leads to a few failed tests:
```
======================================================================== short test summary info =========================================================================
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-0-in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-0-not in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-1-in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-1-not in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-2-in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-2-not in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-3-in] - AssertionError: Input are different
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPandas::test_compound_invert_op[4-3-not in] - AssertionError: Input are different
```