Made reuse of non-shared vector optional in cast pipeline.

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

...s/src/com/oracle/truffle/r/nodes/builtin/CastBuilder.java

...om/oracle/truffle/r/nodes/builtin/casts/PipelineStep.java

...cle/truffle/r/nodes/builtin/casts/PipelineToCastNode.java

...truffle/r/nodes/builtin/casts/fluent/PipelineBuilder.java

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

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

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

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

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