SI-6387 Copy overriding accessor when expanding its name
When the compiler wants to make certain symbol accessible, it
 elevates the symbol with otherwise private visibility and expands
 its name to append the full name of containing class to avoid
 clashes.

In the rare cases when the accessor overrides the member in base
 class, such expanding either results in AbstractMethodError when
 the base method is abstract, or, even worse, can change the
 semantics of the program.

To avoid such issues, we clone the accessor symbol, clear its
 ACCESSOR flag and enter the symbol with an unchanged name.

This change only adds lost overridden methods, so the PR targets
 2.10.x