new symbol lookup and assumption mechanism, introduce LocalReadVariableNode

...fle.r.engine/src/com/oracle/truffle/r/engine/REngine.java

...rc/com/oracle/truffle/r/engine/RRuntimeASTAccessImpl.java

...c/com/oracle/truffle/r/nodes/builtin/base/AsFunction.java

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

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

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

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

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

...cle/truffle/r/nodes/builtin/base/S3DispatchFunctions.java

.../oracle/truffle/r/nodes/builtin/base/StandardGeneric.java

...c/com/oracle/truffle/r/nodes/builtin/base/UpdateSlot.java

...fle.r.nodes/src/com/oracle/truffle/r/nodes/RASTUtils.java

...fle.r.nodes/src/com/oracle/truffle/r/nodes/RRootNode.java

...nodes/src/com/oracle/truffle/r/nodes/RTruffleVisitor.java

...acle/truffle/r/nodes/access/AccessEnclosingFrameNode.java

.../src/com/oracle/truffle/r/nodes/access/FrameSlotNode.java

...cle/truffle/r/nodes/access/ReadVariadicComponentNode.java

...e/truffle/r/nodes/access/WriteLocalFrameVariableNode.java

...e/truffle/r/nodes/access/WriteSuperFrameVariableNode.java

...uffle/r/nodes/access/variables/LocalReadVariableNode.java