Fix incorrect comparison for value types containing reference fields

[rokklobster]

DefaultComparison have higher priority than ComplexComparison, and value types are checked using this comparison. However, due to Equals semantics for value types, if type contains field of reference type, fields are compared using referential equality.

Fix introduces check whether types compared are value types holding reference type fields in both DefaultComparison and ComplexComparison. Added a test to check this behavior; all tests green