Implement R_alloc as up-call & refactor all RFFI state from RContext to RFFIContext

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

...truffle/r/ffi/impl/llvm/TruffleLLVM_RFFIContextState.java

...acle/truffle/r/ffi/impl/llvm/TruffleLLVM_RFFIFactory.java

.../truffle/r/ffi/impl/llvm/TruffleLLVM_UpCallsRFFIImpl.java

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

...mpl/src/com/oracle/truffle/r/ffi/impl/nfi/NFIContext.java

...oracle/truffle/r/ffi/impl/nfi/TruffleNFI_RFFIFactory.java

...le/truffle/r/ffi/impl/nfi/TruffleNFI_UpCallsRFFIImpl.java

.../oracle/truffle/r/ffi/impl/upcalls/MemoryUpCallsRFFI.java

.../src/com/oracle/truffle/r/ffi/processor/FFIProcessor.java

...oracle.truffle.r.native/fficall/src/common/rffi_upcalls.h

...e.truffle.r.native/fficall/src/common/rffi_upcallsindex.h

...ve/fficall/src/truffle_common/Rinternals_truffle_common.h

com.oracle.truffle.r.native/fficall/src/truffle_nfi/Memory.c

...me/src/com/oracle/truffle/r/runtime/context/RContext.java

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

...untime/src/com/oracle/truffle/r/runtime/ffi/CallRFFI.java

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

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