RStringVector handled specifically when passed over via CRFFI

...oracle/truffle/r/ffi/impl/common/JavaUpCallsRFFIImpl.java

...fle/r/ffi/impl/interop/FFI_RForeignAccessFactoryImpl.java

...src/com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_C.java

...racle/truffle/r/ffi/impl/managed/Managed_RFFIFactory.java

...l/src/com/oracle/truffle/r/ffi/impl/nfi/TruffleNFI_C.java

...le/r/nodes/builtin/base/foreign/FortranAndCFunctions.java

...c/com/oracle/truffle/r/runtime/data/NativeDataAccess.java

.../src/com/oracle/truffle/r/runtime/data/RStringVector.java

...com/oracle/truffle/r/runtime/data/StringArrayWrapper.java

...r.runtime/src/com/oracle/truffle/r/runtime/ffi/CRFFI.java

...m/oracle/truffle/r/runtime/ffi/CRFFIUnwrapVectorNode.java

...com/oracle/truffle/r/runtime/ffi/CRFFIWrapVectorNode.java

...e.r.runtime/src/com/oracle/truffle/r/runtime/ffi/DLL.java

...ime/src/com/oracle/truffle/r/runtime/ffi/InvokeCNode.java

...c/com/oracle/truffle/r/runtime/ffi/VectorRFFIWrapper.java