Also push the onconnect event for the initial connection.
This still doesn't properly handle sending an onconnect event to a
pre-existing SharedWorkerGlobalScope with the same name for the same
origin, but it does give us a lot of WPT passes in the SharedWorker
category.
Shared workers are essentially just workers that may be accessed from
scripts within the same origin. There are plenty of FIXMEs here (mostly
building on existing worker FIXMEs that are already in place), but this
lets us run the shared worker variants of WPT tests.
