Endless loop in MultiViewHandler.normalizeRequestURI

[pdudits]

Describe the bug

When FacesServlet is mapped to /* or invoked via forwarding where other servlet has this mapping, the view processing never terminates as it is stuck in while loop in MultiViewHandler.normalizeRequestURI. mapping is "" in this case and therefore loop condition is always true and the viewId never changes.

To Reproduce

Steps to reproduce the behavior:

1. Set mapping of facesServlet to /*
2. Make a request to a view
3. Observe infinite loop

Expected behavior

Request processing should terminate. Given that /* is rare but valid entry, it shouldn't try any normalization

Additional context

Will provide PR for version 4, master is not buildable at this time.