LibJS: Throw TypeError when coercing symbol to number

Author: https://github.com/linusg
Commit: 4569e88bea
Pull-request: https://github.com/SerenityOS/serenity/pull/2270
Issue: https://github.com/SerenityOS/serenity/issues/2267

Libraries/LibJS/Runtime/Value.cpp

@@ -231,8 +231,8 @@ Value Value::to_number(Interpreter& interpreter) const
         return Value(parsed_double);
     }
     case Type::Symbol:
-        // FIXME: Get access to the interpreter and throw a TypeError
-        ASSERT_NOT_REACHED();
+        interpreter.throw_exception<TypeError>("Can't convert symbol to number");
+        return {};
     case Type::Object:
         auto primitive = m_value.as_object->to_primitive(Object::PreferredType::Number);
         if (interpreter.exception())