Refactoring.

.../src/com/oracle/truffle/r/nodes/builtin/base/Combine.java

...c/com/oracle/truffle/r/nodes/builtin/base/UpdateAttr.java

...oracle/truffle/r/nodes/builtin/base/UpdateAttributes.java

...src/com/oracle/truffle/r/nodes/unary/CastComplexNode.java

.../src/com/oracle/truffle/r/nodes/unary/CastDoubleNode.java

...src/com/oracle/truffle/r/nodes/unary/CastIntegerNode.java

...src/com/oracle/truffle/r/nodes/unary/CastLogicalNode.java

....nodes/src/com/oracle/truffle/r/nodes/unary/CastNode.java

...des/src/com/oracle/truffle/r/nodes/unary/CastRawNode.java

.../src/com/oracle/truffle/r/nodes/unary/CastStringNode.java