Remove unnecessary AST node for ++ and -- operations.

src/full-codegen.cc

Index: src/full-codegen.cc
===================================================================
--- src/full-codegen.cc	(revision 7507)
+++ src/full-codegen.cc	(working copy)
@@ -213,12 +213,6 @@
 }
 
 
-void BreakableStatementChecker::VisitIncrementOperation(
-    IncrementOperation* expr) {
-  UNREACHABLE();
-}
-
-
 void BreakableStatementChecker::VisitProperty(Property* expr) {
   // Property load is breakable.
   is_breakable_ = true;
@@ -1357,11 +1351,6 @@
 }
 
 
-void FullCodeGenerator::VisitIncrementOperation(IncrementOperation* expr) {
-  UNREACHABLE();
-}
-
-
 int FullCodeGenerator::TryFinally::Exit(int stack_depth) {
   // The macros used here must preserve the result register.
   __ Drop(stack_depth);