the dimensions accessors reviewed

...n/src/com/oracle/truffle/r/nodes/builtin/base/Matrix.java

...rc/com/oracle/truffle/r/nodes/builtin/base/Transpose.java

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

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

...me/src/com/oracle/truffle/r/runtime/data/RExpression.java

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

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

...acle/truffle/r/runtime/data/model/RAbstractContainer.java