ESM coverage: async parent executing after rejection in different branch of a graph

[nicolo-ribaudo]

I don't see tests for this, and I'm getting different results across different browsers.

Test case:

// entrypoint
import("./foo.js").then(console.log.bind(console, "RES"), console.log.bind(console, "REJ"));

// foo.js
import "./a.js";
import "./b.js";

// a.js
import "./c.js";
console.log("RUNNING a.js");

// c.js
await new Promise(res => setTimeout(res, 1000));

// b.js
throw new Error("b.js failed to run");

The expected behavior is that we first reject the dynamic import promise logging the error from b.js, and then after 1 second we log RUNNING a.js.