Optimizers with high atols should likely be using np.complex128

[dabacon]

We have flakes on tests that have quite high atols due to the move from np.complex128 to np.complex64 default. See #5535 for example. These are sometimes optimizers that are very numerically unstable. We should likely use np.complex128 for these optimizers (say ones with atols of 2e-5 or worse)

[dabacon]

We have rolled back the change in default #5636 so this is no longer a relevant issue.