[Interpreter] Preserve source positions in peephole optimizer.

src/interpreter/bytecode-peephole-optimizer.h

Index: src/interpreter/bytecode-peephole-optimizer.h
diff --git a/src/interpreter/bytecode-peephole-optimizer.h b/src/interpreter/bytecode-peephole-optimizer.h
index 19813958cd8ff56d83bb33f7e3d2943b08aa4243..4f2cd1895d88f212ee49abc58b4efb37ea4c1e8e 100644
--- a/src/interpreter/bytecode-peephole-optimizer.h
+++ b/src/interpreter/bytecode-peephole-optimizer.h
@@ -29,9 +29,11 @@ class BytecodePeepholeOptimizer final : public BytecodePipelineStage,
  private:
   BytecodeNode* Optimize(BytecodeNode* current);
 
-  void UpdateCurrentBytecode(BytecodeNode* const current);
+  void UpdateLastAndCurrentBytecodes(BytecodeNode* const current);
   bool CanElideCurrent(const BytecodeNode* const current) const;
   bool CanElideLast(const BytecodeNode* const current) const;
+  bool CanElideLastBasedOnSourcePosition(
+      const BytecodeNode* const current) const;
 
   void InvalidateLast();
   bool LastIsValid() const;