Add option to disable computing static properties on FlowStart

[Suficio]

Option is useful when dealing with a configuration that doesn't compute static properties on any components but FlowStart.

This change saves a bit of computational time, but also can handle an edge-case where mass flow is zero without error.

[JustinSGray]

Thanks for the PR. We can accept this, but Id like to keep the same option name as the other elements: https://github.com/OpenMDAO/pyCycle/blob/master/pycycle/elements/compressor.py#L393-L394

we used statics as the option name everywhere else. if you make it match, I can pull this in.