Align no isolation worker api classloader requirement with isolated modes

[ghale]

Although no-isolation workers don't have any classloader isolation, they do have the requirement that they run in the same classloader as the task that submits them. We've recently discovered that there is a pathological case in composite builds where a worker can accidentally get a classloader from a different build in the composite (see #10317). We have a hacky fix for this in 5.6.1 (#10335), but we should come up with a better solution that aligns this requirement with how we communicate the classloader requirements for the classloader isolation and process isolation cases.