[Interpreter] Add support for for count operations.

test/unittests/interpreter/bytecode-array-builder-unittest.cc

Index: test/unittests/interpreter/bytecode-array-builder-unittest.cc
diff --git a/test/unittests/interpreter/bytecode-array-builder-unittest.cc b/test/unittests/interpreter/bytecode-array-builder-unittest.cc
index 2654923b55afa73ad1e39a136d2c37edd79dc507..f98b6a575a62359c134a6792a6252ed007a13e57 100644
--- a/test/unittests/interpreter/bytecode-array-builder-unittest.cc
+++ b/test/unittests/interpreter/bytecode-array-builder-unittest.cc
@@ -92,9 +92,14 @@ TEST_F(BytecodeArrayBuilderTest, AllBytecodesGenerated) {
       .BinaryOperation(Token::Value::SAR, reg, Strength::WEAK)
       .BinaryOperation(Token::Value::SHR, reg, Strength::WEAK);
 
+  // Emit count operatior invocations
+  builder.CountOperation(Token::Value::ADD, Strength::WEAK)
+      .CountOperation(Token::Value::SUB, Strength::WEAK);
+
   // Emit unary operator invocations.
   builder.LogicalNot().TypeOf();
 
+
   // Emit new.
   builder.New(reg, reg, 0);
 
@@ -111,7 +116,7 @@ TEST_F(BytecodeArrayBuilderTest, AllBytecodesGenerated) {
       .CompareOperation(Token::Value::IN, reg, Strength::WEAK);
 
   // Emit cast operator invocations.
-  builder.LoadNull()
+  builder.CastAccumulatorToNumber()
       .CastAccumulatorToBoolean()
       .CastAccumulatorToName();