Cleanup experimental/streams and experimental/fs after #4017

[mstoykov]

Problem:

Experimental/streams uses a lot of promises and during #4017 it seemed way nicer to return errors upwards in most cases, but instead I had to panic or rewrite big parts of the module.

As such I choose to get the change out especially as experimental/streams is currently fairly lightly used. Similar is the situation with experimental/fs but to a lesser degree.

Solution:

It will be nice if both modules propagate errors upwards and let Sobek handle it.

As well as having tests that this work well with the interrupt - which will likely require quite a lot of tests.