fix props & emits proto

[LongTengDao]

1. props (main):

Any key in Object.prototype such as valueOf can not be a prop to receive currently.

Vue.createApp({
    template: '<MyComponent />',
    components: {
        MyComponent: {
            template: '<div>{{ valueOf }}<br>{{ toString }}</div>',
            props: {
                valueOf: { default: 'v' },
                toString: { },
            },
        },
    },
}).mount('body');

prop will get function value instead of undefined or default option.

2. emits (incidental):

$emit("__defineGetter__") may cause bug.

[posva]

I would say it's better not to be able to receive a prop that conflicts with existing properties en objects. As well as emitting an event named __defineGetter__ which is unrealistic in an application.

Having objects with the Object prototype benefit from methods like keys

[LongTengDao]

doc said the only rule is not to use key start with _ or $, if this is intended and won't be fix, I think it will be good to write in doc and make a warn check in Vue, not treat it as if it not happen

[LongTengDao]

the main problem won't happen in components, and the root component rarely has props, so this PR is not necessary.