LibJS: Log when we throw a JavaScript Error

This makes debugging a lot easier since we actually learn that an Error
got thrown.

Libraries/LibJS/Interpreter.cpp

@@ -206,6 +206,10 @@ Value Interpreter::call(Function* function, Value this_value, const Vector<Value
 
 Value Interpreter::throw_exception(Exception* exception)
 {
+    if (exception->value().is_object() && exception->value().as_object().is_error()) {
+        auto& error = static_cast<Error&>(exception->value().as_object());
+        dbg() << "Throwing JavaScript Error: " << error.name() << ", " << error.message();
+    }
     m_exception = exception;
     unwind(ScopeType::Try);
     return {};