[interpreter] Introduce fused bytecodes for common sequences.

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 4f2cd1895d88f212ee49abc58b4efb37ea4c1e8e..95de51c3ea19b5793dc381ba1aad5e81d5b1801a 100644
--- a/src/interpreter/bytecode-peephole-optimizer.h
+++ b/src/interpreter/bytecode-peephole-optimizer.h
@@ -29,12 +29,18 @@ class BytecodePeepholeOptimizer final : public BytecodePipelineStage,
  private:
   BytecodeNode* Optimize(BytecodeNode* current);
 
-  void UpdateLastAndCurrentBytecodes(BytecodeNode* const current);
+  void TryToRemoveLastExpressionPosition(const BytecodeNode* const current);
+  bool TransformLastAndCurrentBytecodes(BytecodeNode* const current);
   bool CanElideCurrent(const BytecodeNode* const current) const;
   bool CanElideLast(const BytecodeNode* const current) const;
   bool CanElideLastBasedOnSourcePosition(
       const BytecodeNode* const current) const;
 
+  // Simple substitution methods.
+  bool RemoveToBooleanFromJump(BytecodeNode* const current);
+  bool RemoveToBooleanFromLogicalNot(BytecodeNode* const current);
+  bool ChangeLdaToLdr(BytecodeNode* const current);
+
   void InvalidateLast();
   bool LastIsValid() const;
   void SetLast(const BytecodeNode* const node);