H2/QUIC requests don't fire RequestFinished

[patrickhulce]

while investigating #5249, I noticed that the page always timed out while waiting for load because of 3 network requests to a Google origin that were using QUIC/H2, it seems that they never "finish" in the traditional sense and that the end of the request is simply the receivedHeadersEnd.

URL: https://www.guidetoonlineschools.com/online-schools
QUIC requests: https://apis.google.com/se/0/_/+1/fastbutton?usegapi=1&size=medium&origin=https%3A%2F%2Fwww.guidetoonlineschools.com&url=https%3A%2F%2Fwww.guidetoonlineschools.com%2Fonline-schools&gsrc=3p&ic=1&jsh=m%3B%2F_%2Fscs%2Fapps-static%2F_%2Fjs%2Fk%3Doz.gapi.en_US.YrtA5yEj3Q0.O%2Fm%3D__features__%2Fam%3DQQE%2Frt%3Dj%2Fd%3D1%2Frs%3DAGLTcCN0sMuxpka3R31qPm4lRzkEwQAp8Q