[GR-5982] Polyglot API should support multidimensional arrays.

...src/com/oracle/truffle/r/nodes/builtin/base/AsVector.java

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

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

...acle/truffle/r/nodes/access/vector/ExtractVectorNode.java

...racle/truffle/r/nodes/binary/BinaryBooleanScalarNode.java

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

.../src/com/oracle/truffle/r/nodes/unary/CastDoubleNode.java

...src/com/oracle/truffle/r/nodes/unary/CastIntegerNode.java

...es/src/com/oracle/truffle/r/nodes/unary/CastListNode.java

...src/com/oracle/truffle/r/nodes/unary/CastLogicalNode.java

.../src/com/oracle/truffle/r/nodes/unary/CastStringNode.java

.../com/oracle/truffle/r/nodes/unary/ConvertBooleanNode.java

...acle/truffle/r/nodes/unary/UnaryArithmeticReduceNode.java

...es/src/com/oracle/truffle/r/nodes/unary/UnaryNotNode.java

.../com/oracle/truffle/r/runtime/interop/ForeignArray2R.java

...est/src/com/oracle/truffle/r/test/ExpectedTestOutput.test

.../oracle/truffle/r/test/library/fastr/TestJavaInterop.java