[Interpreter] Add support for short (16 bit) operands.

src/compiler/interpreter-assembler.h

Index: src/compiler/interpreter-assembler.h
diff --git a/src/compiler/interpreter-assembler.h b/src/compiler/interpreter-assembler.h
index 67ab9cc2a9da4444105ad6aa4f5a6f66be847652..1ce2ef9625227d5ff702410cc6d43a45812d1558 100644
--- a/src/compiler/interpreter-assembler.h
+++ b/src/compiler/interpreter-assembler.h
@@ -52,6 +52,10 @@ class InterpreterAssembler {
   // current bytecode.
   Node* BytecodeOperandReg(int operand_index);
 
+  // Returns the index immediate for the wide bytecode operand |operand_index|
+  // in the current bytecode.
+  Node* BytecodeOperandWideIdx(int operand_index);
+
   // Accumulator.
   Node* GetAccumulator();
   void SetAccumulator(Node* value);
@@ -148,6 +152,7 @@ class InterpreterAssembler {
   Node* SmiShiftBitsConstant();
   Node* BytecodeOperand(int operand_index);
   Node* BytecodeOperandSignExtended(int operand_index);
+  Node* BytecodeOperandWide(int operand_index);
 
   Node* CallIC(CallInterfaceDescriptor descriptor, Node* target, Node** args);
   Node* CallJSBuiltin(int context_index, Node* receiver, Node** js_args,