can-construct@3.5.4 started setting a Symbol as well as the __inSetup property.

can-define@2.7.8 started using the Symbol instead of the property (this was done to fix can-define#421)

These are the steps to remove the remaining usages of the __inSetup property:

• Update can-map to use the new can-construct and to read the Symbol instead of the property
• Update can-map-define to use the new can-map and to read the Symbol instead of the property
• Update can-simple-map to use the new can-construct
• Update can-event-queue to read the Symbol instead of the property
• Update can-define, can-map, can-map-define, can-simple-map to use the new can-event-queue

I think after this is done, we can remove the property from can-construct, possibly in the next major release or earlier if we think it's worthwhile.

We can break this up into other issues, I just wanted to put it all in one place so it could be discussed.