Improve exception thrown when calling a invalid constructor

[harumazzz]

On this simple js code:

const objLiteral = {};  
const instance = new objLiteral();

In engine v8, the error will be: TypeError: objLiteral is not a constructor

However, in quickjs-ng: not a constructor

Test 2:

const num = 42;
const instance = new num();

Test 3:

const test_func = () => {};
const instance = new test_func(); 

In all of these cases quickjs-ng throw the exception "not a constructor", while in engine v8 the error is more clear like num is not a constructor or test_func is not a constructor. Can this be improved?

[bnoordhuis]

Known issue. I worked on it back in December in my imaginatively named not-a-constructor branch; it handles the simple cases but it's not a comprehensive fix. You're welcome to adopt, update and PR it.