Add tests that as.xyz do not copy the vector if possible

...le/truffle/r/runtime/data/nodes/SlowPathVectorAccess.java

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

...acle/truffle/r/test/builtins/TestBuiltin_ascharacter.java

...oracle/truffle/r/test/builtins/TestBuiltin_ascomplex.java

.../oracle/truffle/r/test/builtins/TestBuiltin_asdouble.java

...cle/truffle/r/test/builtins/TestBuiltin_asexpression.java

...oracle/truffle/r/test/builtins/TestBuiltin_asinteger.java

...om/oracle/truffle/r/test/builtins/TestBuiltin_aslist.java

...oracle/truffle/r/test/builtins/TestBuiltin_aslogical.java

...com/oracle/truffle/r/test/builtins/TestBuiltin_asraw.java