Revert "[Truffle] Remove useless node copy constructors."

This reverts commit 391076d550df9dd8928a54331981f308c44dd257.
[Truffle] Fix bad copy constructors.
Revert "[Truffle] Remove useless copy constructors in NilClassNodes."

This reverts commit 476bd7f4c07c99e16d363312882e9376879090a2.