Add tests for obsolete "nested class is inaccessible"

 #KT-3535 Obsolete
 #KT-3647 Obsolete
 #KT-3731 Obsolete
Delete unused JavaSignatureFormatter
Fix Double and Float equality/hashCode in data classes

 #KT-5818 Fixed
Generate lambdas in enum entry super calls

 #KT-4423 Fixed
Prohibit to override equals/hashCode in enums

 #KT-5721 Fixed
Add toString() to kotlin.Enum

Overridable because it is in java.lang.Enum
Make enum classes comparable

 #KT-3727 Fixed
Regenerate test data on enums

Now they have final equals, hashCode and compareTo