Redundant tests for symbol identity

[MariusDoe]

In KoanAboutSymbols, test02symbolsCanBeCompared and test03identicalSymbolsAreASingleIdenticalObject are redundant. Symbol identity is already shown in the former, thus the latter shows nothing new.

A potential fix might be changing the former to show equality (=) and inequality (~=) instead, leaving the latter to demonstrate identity (==).