Fix JS Generator

```
[OK] G1_HelloWorld (node test/w/G1_HelloWorld.js)
[OK] G2_BinaryOperator (node test/w/G2_BinaryOperator.js)
[OK] G2_Function (node test/w/G2_Function.js)
[OK] G2_Grouping (node test/w/G2_Grouping.js)
[OK] G3_FunctionNoReturn (node test/w/G3_FunctionNoReturn.js)
[OK] G3_FunctionParameter (node test/w/G3_FunctionParameter.js)
[OK] G3_If (node test/w/G3_If.js)
[OK] G3_Let (node test/w/G3_Let.js)
[OK] G3_Prototype (node test/w/G3_Prototype.js)
[OK] G3_Throw (node test/w/G3_Throw.js)
[OK] G3_Try (node test/w/G3_Try.js)
[OK] G3_Var (node test/w/G3_Var.js)
[OK] G3_While (node test/w/G3_While.js)
[OK] G3_WhileBreak (node test/w/G3_WhileBreak.js)
[OK] G4_Boolean (node test/w/G4_Boolean.js)
[OK] G4_Float (node test/w/G4_Float.js)
[OK] G4_Int (node test/w/G4_Int.js)
[OK] G4_IntArray (node test/w/G4_IntArray.js)
[FAILED] G4_IntMap (node test/w/G4_IntMap.js)
[OK] G4_Null (node test/w/G4_Null.js)
[OK] G4_String (node test/w/G4_String.js)
[FAILED] G4_ZeroDivided (node test/w/G4_ZeroDivided.js)
[OK] G5_ApplyFunction (node test/w/G5_ApplyFunction.js)
[OK] G5_LetFunction (node test/w/G5_LetFunction.js)
[OK] G5_VarFunction (node test/w/G5_VarFunction.js)
[FAILED] G6_Class (node test/w/G6_Class.js)
[OK] G6_Constructor (node test/w/G6_Constructor.js)
[FAILED] G6_DynamicBinding (node test/w/G6_DynamicBinding.js)
[FAILED] G6_InstanceOf (node test/w/G6_InstanceOf.js)
[FAILED] G6_SubClass (node test/w/G6_SubClass.js)
[OK] G7_InferFunction (node test/w/G7_InferFunction.js)
[OK] G8_Continue (node test/w/G8_Continue.js)
[OK] G8_Math (node test/w/G8_Math.js)
[FAILED] G9_BinaryTrees (node test/w/G9_BinaryTrees.js)
[OK] G9_BubbleSort (node test/w/G9_BubbleSort.js)
[OK] G9_Fibonacci (node test/w/G9_Fibonacci.js)
[OK] G9_MathSqrt (node test/w/G9_MathSqrt.js)
[FAILED] Gx_Closure (node test/w/Gx_Closure.js)
[OK] Gx_EvenOdd (node test/w/Gx_EvenOdd.js)
[OK] Gx_Utf8String (node test/w/Gx_Utf8String.js)
# of OK: 32, # of FAILED: 8
```