Restore identity of upcasted MPL object on method call

When base class method was invoked using case/super method
polymorphic method resolution mechanism didn't worked as
expected. Now object identity is restored after DSL finds
base class method and polymorphic calls work as they should

Change-Id: I670ffaf5b28a60a3d269e85d25e0dfc7e164ee15
Closes-Bug: #1314618
Merge "Restore identity of upcasted MPL object on method call"