[turbofan] Use FrameStatesBeforeAndAfter to simplify handling of before/after frame states in AstGr…

src/compiler/ast-graph-builder.h

Index: src/compiler/ast-graph-builder.h
diff --git a/src/compiler/ast-graph-builder.h b/src/compiler/ast-graph-builder.h
index f9d447256f4eefb4d24b752f15196a30eb16abff..83a488fe11cf8a4a41feaaef1c51d6ba3712ba8c 100644
--- a/src/compiler/ast-graph-builder.h
+++ b/src/compiler/ast-graph-builder.h
@@ -67,6 +67,7 @@ class AstGraphBuilder : public AstVisitor {
   class ControlScopeForCatch;
   class ControlScopeForFinally;
   class Environment;
+  class FrameStateBeforeAndAfter;
   friend class ControlBuilder;
 
   Zone* local_zone_;
@@ -212,9 +213,6 @@ class AstGraphBuilder : public AstVisitor {
   void PrepareFrameState(
       Node* node, BailoutId ast_id,
       OutputFrameStateCombine combine = OutputFrameStateCombine::Ignore());
-  void PrepareFrameStateAfterAndBefore(Node* node, BailoutId ast_id,
-                                       OutputFrameStateCombine combine,
-                                       Node* frame_state_before);
 
   BitVector* GetVariablesAssignedInLoop(IterationStatement* stmt);