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

test/unittests/compiler/interpreter-assembler-unittest.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_UNITTESTS_COMPILER_INTERPRETER_ASSEMBLER_UNITTEST_H_
 #define V8_UNITTESTS_COMPILER_INTERPRETER_ASSEMBLER_UNITTEST_H_
 
 #include "src/compiler/interpreter-assembler.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 25 matching lines @@
                           const Matcher<Node*>& index_matcher);
     Matcher<Node*> IsStore(const Matcher<StoreRepresentation>& rep_matcher,
                            const Matcher<Node*>& base_matcher,
                            const Matcher<Node*>& index_matcher,
                            const Matcher<Node*>& value_matcher);
     template <class... A>
     Matcher<Node*> IsCall(
         const Matcher<const CallDescriptor*>& descriptor_matcher,
         A... args);
 
-    Matcher<Node*> IsBytecodeOperand(int operand);
-    Matcher<Node*> IsBytecodeOperandSignExtended(int operand);
+    Matcher<Node*> IsBytecodeOperand(int offset);
+    Matcher<Node*> IsBytecodeOperandSignExtended(int offset);
+    Matcher<Node*> IsBytecodeOperandShort(int offset);
 
     using InterpreterAssembler::call_descriptor;
     using InterpreterAssembler::graph;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(InterpreterAssemblerForTest);
   };
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_UNITTESTS_COMPILER_INTERPRETER_ASSEMBLER_UNITTEST_H_