Remove the half-implemented and unused `CollectionRangeDeleter` from the 3.4 codebase

The rewrite of the RangeDeleter to be better integrated with the metadata which is actively in use started in 3.4, but didn't finish in time to be released so we now have some dead code, which is being compiled and linked with the rest of mongod.

We should get rid of it (and the associated unit-tests) so it doesn't cause confusion about which exactly is the Range Deleter code.