(PUP-3665) Fix resource overrides for 4x collector

Prior to this commit, the new implementation of collections caused
overrides to fail if the given attribute was a Resource. This was
because 3x required an instance of Resource rather than PResource
Type. In order to fix this issue, transform the override attribute
into the appropriate format for the 3x compiler.
Merge pull request #3307 from hkenney/issue/stable/PUP-3665_fix_collection_resource_overrides_with_future_parser

(PUP-3665) Fix resource overrides for 4x collector