RFunction enclosing frames never change

.../com/oracle/truffle/r/nodes/builtin/RBuiltinPackages.java

...tin/src/com/oracle/truffle/r/nodes/builtin/base/Args.java

...com/oracle/truffle/r/nodes/builtin/base/EnvFunctions.java

...le/truffle/r/nodes/access/variables/ReadVariableNode.java

...acle/truffle/r/nodes/function/FunctionExpressionNode.java

...le/truffle/r/nodes/function/signature/RArgumentsNode.java

....runtime/src/com/oracle/truffle/r/runtime/RArguments.java

....runtime/src/com/oracle/truffle/r/runtime/RSerialize.java

...e/src/com/oracle/truffle/r/runtime/data/RDataFactory.java

...time/src/com/oracle/truffle/r/runtime/data/RFunction.java