XMLHttpRequest: response stream errors #27778
https://crbug.com/602051 Service worker doesn't intercept sync XHR requests.
We can write a test with https://github.com/web-platform-tests/wpt/blob/master/fetch/api/resources/bad-chunk-encoding.py alternatively.
@yutakahirano thanks for identifying that! I was wondering if there were non-ReadableStream ways to trigger this condition. That will make testing less cumbersome going forward and also reduces my worry about this being not handled well across callers (although most specification callers of fetch do not seem to account for it at the moment).