As serializing IPCStream no longer requires a manager or FileDescriptor array,
the arguments are no longer necessary, and can be removed. The AutoIPCStream
helper can also be removed, as managed actors are no longer used for
serialization, so a delayed start callback is not necessary.
The delayed start parameter is also removed from nsIIPCSerializableInputStream
instances, but is still present as `aAllowLazy` on the toplevel serialization
methods.
Differential Revision: https://phabricator.services.mozilla.com/D141048
