Spies forward -isEqual and -hash to the original object

NSProxy overrides `-isEqual` and `-hash`, leading to these methods behaving differently once an object has been spied upon. This code forwards those calls on to the actual object, just as is done for other methods such as `-description`.

This fixes #67247100.

NOTE: Another potential approach to this issue could be to stop using NSProxy as the CDRSpy's base class. E.g. see [here](https://github.com/mikeash/MAFuture/blob/master/MAProxy.m) and discussion [here](https://www.mikeash.com/pyblog/friday-qa-2010-02-26-futures.html)