More fixes enabling knitr

...com/oracle/truffle/r/library/fastrGrid/grDevices/PDF.java

...ruffle/r/library/fastrGrid/grDevices/R/fastrGridDevices.R

...om/oracle/truffle/r/nodes/builtin/base/GrepFunctions.java

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

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

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

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

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

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

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

...c/com/oracle/truffle/r/test/builtins/TestBuiltin_sub.java