Move state saving to getUserEventState()

Update JsfView so that state saving no longer occurs during
processUserEvent(). This is required to ensure that Mojarra's
StateContext.release(...) method is not called too early.

Prior to Mojarra 2.1.16 multiple calls to saveView had no side effects,
but the fix to JAVASERVERFACES-2609 changed this behavior.

In order to retain the fix for SWF-1577 the saveState() method is now
called from getUserEventState(). This should ensure that the
StateContext$AddRemoveListerner is still removed, even when WebFlow
bypasses the usual state saving for certain flow redirects.

Issue: SWF-1631