Scipy vs JIT interpolation test for v4

#1816 introduced `test_scipy_vs_jit()` to compare interpolation methods between scipy and JIT mode. This was removed in the JIT cleanup for v4, but it would be good to add a test on the v4-dev branch which has these values from JIT saved as raw data to be compared against. This would be helpful so that we don't have any regressions on our interpolation schemes.