JSC version:
5a5dc5a5c26808fa98392aecc83d38935b72d255

Build options:
```
./Tools/Scripts/build-jsc --jsc-only --debug
```

test case:
```
function opt(){
	var x = -19278.05 >>> String;
	var y = x + -19278.05;
	var z = y >> String;
	return z;
}

let a = opt();

print("result before JIT opt")
print(a);

for(let i=0; i<0x200; i++){
	opt();
}

let b = opt();

print("result after JIT opt")
print(b);

```

Result:
```
result before JIT opt
-38557
result after JIT opt
-38556
```