function isDefaultPropsDeclaration(node) {
  const propName = astUtil.getPropertyName(node);
  return (propName === 'defaultProps' || propName === 'getDefaultProps');
}
Checks if the Identifier node passed in looks like a defaultProps declaration.
@param {ASTNode} node The node to check. Must be an Identifier node.
@returns {boolean} `true` if the node is a defaultProps declaration, `false` if not