Generated output is incompatible with Jest (again)

[nex3]

This is the same issue as https://github.com/protocolbuffers/protobuf/issues/9152, which was notionally fixed in https://github.com/protocolbuffers/protobuf/pull/9156. However, it seems that as of 3.20.3 the output is (still? again?) the Jest-incompatible

var global = (function() { return this || window || global || self || Function('return this')(); }).call(null);

For now I've rolled back to 3.11.2 which emits the compatible

var global = Function('return this')();

but this isn't a great long-term solution.