Assertion failure in JavascriptArray.cpp

the following poc cause a assertion failure in "debug" build on ubuntu.

```
function opt(){
const v2 = [-1000000000.0];
v2.length = 4294967295;
const v3 = v2.copyWithin();
return v3;
}

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