We should use the "length" property instead of the internal arraybuffer's length
JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu
Also a minor update to the FromPropertyDescriptor operation since in ES6 we can use a property
descriptor whitout any keys
JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu