various interop fixes and improvements

...om/oracle/truffle/r/nodes/builtin/fastr/FastRInterop.java

...acle/truffle/r/nodes/access/vector/ExtractVectorNode.java

...es/src/com/oracle/truffle/r/nodes/function/RCallNode.java

...est/src/com/oracle/truffle/r/test/ExpectedTestOutput.test

...ruffle.r.test/src/com/oracle/truffle/r/test/TestBase.java

.../oracle/truffle/r/test/library/fastr/TestInteropEval.java

....test/src/com/oracle/truffle/r/test/tck/FastRTckTest.java