[GR-6406] Fixes for "foreign" package and testing infrastructure.

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

...src/com/oracle/truffle/r/ffi/impl/nfi/TruffleNFI_DLL.java

.../com/oracle/truffle/r/ffi/impl/nodes/ListAccessNodes.java

...com/oracle/truffle/r/ffi/impl/upcalls/StdUpCallsRFFI.java

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

com.oracle.truffle.r.native/fficall/src/common/util_fastr.c

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

...com/oracle/truffle/r/nodes/builtin/base/Capabilities.java

...acle/truffle/r/nodes/builtin/base/DatePOSIXFunctions.java

...com/oracle/truffle/r/nodes/builtin/base/EncodeString.java

...c/com/oracle/truffle/r/nodes/builtin/base/Expression.java

...om/oracle/truffle/r/nodes/builtin/base/FileFunctions.java

...in/src/com/oracle/truffle/r/nodes/builtin/base/IConv.java

.../oracle/truffle/r/nodes/builtin/base/LocaleFunctions.java

...in/src/com/oracle/truffle/r/nodes/builtin/base/Order.java

...tin/src/com/oracle/truffle/r/nodes/builtin/base/Rank.java

...in/src/com/oracle/truffle/r/nodes/builtin/base/Round.java

...fle/r/nodes/builtin/base/printer/DoubleVectorPrinter.java

....r.runtime/src/com/oracle/truffle/r/runtime/REnvVars.java

...le.r.runtime/src/com/oracle/truffle/r/runtime/RError.java