[GR-2737] Various performance improvements.

...ngine/src/com/oracle/truffle/r/engine/shell/RCommand.java

...ary/src/com/oracle/truffle/r/library/tools/ToolsText.java

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

...m/oracle/truffle/r/nodes/builtin/base/FrameFunctions.java

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

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

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

...n/src/com/oracle/truffle/r/nodes/builtin/base/Strrep.java

...m/oracle/truffle/r/nodes/builtin/base/TraceFunctions.java

...acle/truffle/r/nodes/builtin/base/foreign/WriteTable.java

...le/r/nodes/builtin/base/system/SystemFunctionFactory.java

.../truffle/r/nodes/builtin/helpers/BrowserInteractNode.java

...r.nodes/src/com/oracle/truffle/r/nodes/ffi/RFFIUtils.java

...es/src/com/oracle/truffle/r/nodes/function/RCallNode.java

...c/com/oracle/truffle/r/nodes/objects/DispatchGeneric.java

...uffle.r.runtime/src/com/oracle/truffle/r/runtime/DCF.java

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

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

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

...rc/com/oracle/truffle/r/runtime/conn/TextConnections.java