Normalize the values that R may return via interop

CHANGELOG.md

...ruffle/r/engine/interop/RAbstractVectorAccessFactory.java

...e/truffle/r/engine/interop/RForeignAccessFactoryImpl.java

...src/com/oracle/truffle/r/engine/interop/RInteropNAMR.java

...e/src/com/oracle/truffle/r/engine/interop/RLogicalMR.java

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

...src/com/oracle/truffle/r/runtime/data/RInteropScalar.java

...e/src/com/oracle/truffle/r/runtime/interop/Foreign2R.java

...e/src/com/oracle/truffle/r/runtime/interop/R2Foreign.java

.../oracle/truffle/r/test/engine/interop/AbstractMRTest.java

.../com/oracle/truffle/r/test/engine/interop/ListMRTest.java

...ffle/r/test/engine/interop/RArgsValuesAndNamesMRTest.java

...cle/truffle/r/test/engine/interop/REnvironmentMRTest.java

...oracle/truffle/r/test/engine/interop/RFunctionMRTest.java

.../oracle/truffle/r/test/engine/interop/RLogicalMRTest.java

...oracle/truffle/r/test/engine/interop/RS4ObjectMRTest.java

...om/oracle/truffle/r/test/engine/interop/VectorMRTest.java