Several fixes after rebasing

.../com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_Call.java

...ffle/r/ffi/impl/llvm/TruffleLLVM_DownCallNodeFactory.java

...le.r.launcher/src/com/oracle/truffle/r/launcher/REPL.java

...le.truffle.r.native/fficall/src/truffle_llvm/Rinternals.c

.../oracle/truffle/r/nodes/access/BaseWriteVariableNode.java

...e/truffle/r/runtime/env/frame/REnvTruffleFrameAccess.java

...est.native/packages/testrffi/testrffi/tests/simpleTests.R

mx.fastr/mx_copylib.py

mx.fastr/suite.py