Simplify object creation

Currently new `RegExp` creation is pretty obscure. It may be replaced by less complex statment.

Rationale:
```javascript
var verbalExpression = Object.create( RegExp.prototype );
// New object is created. [[class]] = 'Object', [[prototype]] = RegExp.prototype
// It has same prorotype as RegExp, but this is not RegExp.
// Also, Object.create is unavailable for older browsers

verbalExpression = (
    RegExp.apply( verbalExpression, arguments )
// If arguments[0] is regexp, it would return arguments[0]
// Otherwise it would just create new RegExp using args[0] as pattern and args[1] as flags.
// Pattern will be overwritten upon next .compile call, so it is pretty useless to set anything here.
    || verbalExpression
// RegExp always returns object, so || is always short-circuited
);
```