function isRequireStatement(node) {
      if (node.type === 'CallExpression') {
        if (node.callee.type === 'Identifier') {
          return node.callee.name === 'require';
        }
      }
      if (node.type === 'MemberExpression') {
        return isRequireStatement(node.object);
      }

      return false;
    }
Determines if the given expression is a require statement. Supports
nested MemberExpresions. ie `require('foo').nested.property`
@param {ASTNode} node
@returns {boolean}