[GR-3140] Support for rJava-style interoperability in FastR.

...rc/com/oracle/truffle/r/engine/RRuntimeASTAccessImpl.java

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

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

...ffle/r/nodes/builtin/base/printer/ExternalPtrPrinter.java

...om/oracle/truffle/r/nodes/builtin/fastr/FastRInterop.java

...oracle/truffle/r/nodes/builtin/casts/CastForeignNode.java

com.oracle.truffle.r.pkgs/rJava/DESCRIPTION

com.oracle.truffle.r.pkgs/rJava/NAMESPACE

com.oracle.truffle.r.pkgs/rJava/R/0classes.R

com.oracle.truffle.r.pkgs/rJava/R/J.R

com.oracle.truffle.r.pkgs/rJava/R/arrays.R

com.oracle.truffle.r.pkgs/rJava/R/call.R

com.oracle.truffle.r.pkgs/rJava/R/comparison.R

com.oracle.truffle.r.pkgs/rJava/R/completion.R

com.oracle.truffle.r.pkgs/rJava/R/converter.R

com.oracle.truffle.r.pkgs/rJava/R/exceptions.R

com.oracle.truffle.r.pkgs/rJava/R/import.R

com.oracle.truffle.r.pkgs/rJava/R/instanceof.R

com.oracle.truffle.r.pkgs/rJava/R/jfirst.R

com.oracle.truffle.r.pkgs/rJava/R/jinit.R