[turbofan] The BytecodeGraphBuilder should never insert the empty frame state.

src/compiler/bytecode-graph-builder.h

Index: src/compiler/bytecode-graph-builder.h
diff --git a/src/compiler/bytecode-graph-builder.h b/src/compiler/bytecode-graph-builder.h
index c842c24b8cc8860ec85641d3491551b0e1382543..d665e90b63b587178f6cf648eeff09dbb54d29c5 100644
--- a/src/compiler/bytecode-graph-builder.h
+++ b/src/compiler/bytecode-graph-builder.h
@@ -218,10 +218,6 @@ class BytecodeGraphBuilder {
   const BytecodeBranchAnalysis* branch_analysis_;
   Environment* environment_;
 
-  // Indicates whether deoptimization support is enabled for this compilation
-  // and whether valid frame states need to be attached to deoptimizing nodes.
-  bool deoptimization_enabled_;
-
   // Merge environments are snapshots of the environment at points where the
   // control flow merges. This models a forward data flow propagation of all
   // values from all predecessors of the merge in question.