Revert "Changed the old invulnerable methods from the wither to the new."

This reverts commit d50f8f6f11f69e7e1e56be92fb2d72a5014a3e34.
Revert "Withers now use the new invulnerable."

This reverts commit 619592b5a0ab651e714d55932bc7909e4204cee9.