Delete old unused Polymer versions.


I'm not 100% sure my Codesearching guarantees that we found all the places where these Polymers are used, but I think we don't really have a super reliable way to check for whether these are symlinked anywhere. I figure if this change causes breakages, we can find out then re-add the Polymer versiosn that are still used.

Change-Id: I8897db226c90b45a9b63c6db38088a6de9c14f76