merge and enable testrgen tests

...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

...om/oracle/truffle/r/test/testrgen/TestrGenBuiltinArg.java

...m/oracle/truffle/r/test/testrgen/TestrGenBuiltinConj.java

.../truffle/r/test/testrgen/TestrGenBuiltinDate2POSIXlt.java

...acle/truffle/r/test/testrgen/TestrGenBuiltinEncoding.java

...com/oracle/truffle/r/test/testrgen/TestrGenBuiltinIm.java

...com/oracle/truffle/r/test/testrgen/TestrGenBuiltinLa.java

...om/oracle/truffle/r/test/testrgen/TestrGenBuiltinMod.java

.../truffle/r/test/testrgen/TestrGenBuiltinPOSIXlt2Date.java

...cle/truffle/r/test/testrgen/TestrGenBuiltinPrimitive.java

...com/oracle/truffle/r/test/testrgen/TestrGenBuiltinRe.java

...acle/truffle/r/test/testrgen/TestrGenBuiltinSyschmod.java

...cle/truffle/r/test/testrgen/TestrGenBuiltinSysgetenv.java

...racle/truffle/r/test/testrgen/TestrGenBuiltinSysglob.java

...e/truffle/r/test/testrgen/TestrGenBuiltinSysreadlink.java

...cle/truffle/r/test/testrgen/TestrGenBuiltinSyssetenv.java

.../truffle/r/test/testrgen/TestrGenBuiltinSyssetlocale.java

...acle/truffle/r/test/testrgen/TestrGenBuiltinSyssleep.java