A member export resolves to its binding only when the binding is declared
before the write and never reassigned, so a consumer reads the value the
member stored. A module that re-exports another module's exports through
module.exports = require("./x") now counts its own writes after the
re-exported module's: a member it adds resolves, and a member both modules
write stays refused. The exports rebinding refusal and its test now cover
the form that stays refused, exports = value without module.exports.