[GR-2719] Several fix-ups in CP.

...c/com/oracle/truffle/r/nodes/builtin/CastBuilderTest.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

...odes/builtin/casts/analysis/ForwardingAnalysisResult.java

...fle/r/nodes/builtin/casts/fluent/InitialPhaseBuilder.java

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

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

...src/com/oracle/truffle/r/nodes/unary/CastComplexNode.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

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

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