Make the selector visible for all polymorphic VIs

[volks73]

Some polymorphic VIs have the selector visible, some do not. All polymorphic VIs will automatically select the VI based on the wired inputs, but it is not always obvious what the inputs should be and how the selection occurs. Displaying the selector will make the toolkit easier to understand and use.

I believe I originally hide the selector because I thought it looked messy having a bunch of selectors on the block diagram. There is the Select Type menu item that appears in the right-click, context menu for a polymorphic VI to select the type without displaying the selector, but it is not obvious which VIs are polymorphic unless you are already familiar with the internals of the toolkit.

[volks73]

The polymorphic VI type selector default has been changed from hidden to visible as of 8578066 for all Create/Destroy VIs.