Further cleanup and fixes to cast operations and conversion builtins.

.../com/oracle/truffle/r/nodes/builtin/base/AsCharacter.java

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

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

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

...es/src/com/oracle/truffle/r/nodes/builtin/base/AsRaw.java

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

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

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

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

...des/src/com/oracle/truffle/r/nodes/unary/CastRawNode.java

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

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

...ime/src/com/oracle/truffle/r/runtime/data/RRawVector.java

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

...le.r.test/src/com/oracle/truffle/r/test/all/AllTests.java

...t/src/com/oracle/truffle/r/test/failing/FailingTests.java

.../com/oracle/truffle/r/test/simple/TestSimpleBuiltins.java