isPropertyDefined(node) {
		const entry = this.getPropertyInfo(node);

		return (
			(GET_KIND.test(node.kind) && entry.get) ||
			(SET_KIND.test(node.kind) && entry.set)
		);
	}
Checks whether the given property has been defined already or not.
@param {ASTNode} node The Property node to check.
@returns {boolean} `true` if the property has been defined.