weak-reference-set does not support multiple entries

[RyanMilligan]

How often can you reproduce it?

• [x] Always
• [ ] Sometimes
• [ ] Rarely
• [ ] Unable
• [ ] I didn’t try

Description: WeakReferenceSet's _getIndex function only ever looks at the first item in the set.

Steps to reproduce:

1. Run the following code:

   
   var set = new WeakReferenceSet();
   var item1 = {};
   var item2 = {};
   var item3 = {};

set.addReference(item1); set.addReference(item2); set.addReference(item3);

<!-- Describe what you expected to have happen after completing the steps above. -->

__Expected results:__ Both items are in the set, so both lines should output `true`.

<!-- Describe what actually happened after completing the steps above. -->

__Actual results:__ The output is:

true false

The issue is that [_getIndex](https://github.com/canjs/can-connect/blob/3d1c0347a8e64a9c687e511ff9a303fdbf90fa38/helpers/weak-reference-set.js#L58) never returns true from the callback it passes to `every`, so only the first item is returned. I tried adding `return true;` after the if statement in my local copy and that solved the problem.