Serialize and push/pop callbacks for certain functions from NativeFunction

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

...uffle/r/ffi/impl/managed/Managed_DownCallNodeFactory.java

...ruffle/r/ffi/impl/nfi/TruffleNFI_DownCallNodeFactory.java

...e.truffle.r.native/fficall/src/truffle_common/base_rffi.c

...acle.truffle.r.native/fficall/src/truffle_nfi/Rembedded.c

com.oracle.truffle.r.native/version.source

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

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