Support nonReactive(() => ...) to avoid encouraging the sledgehammer noContext

[benjamn]

The drawback of noContext is that it censors all contextual Slot values from the inner function's context, when the only Slot used by optimism is the parentEntrySlot.

The new nonReactive function is like noContext, but it censors only parentEntrySlot, to avoid registering dependencies while executing certain code known/suspected to contain functions wrapped by optimism.

[jerelmiller]

🎉 Thanks for introducing this!