use unittest.skip
got Makefile in line with 5.0a3 pinnings
get portal_state for context.context
context is a ContentActivity adapter for which portal_url can not be
acquired. context.context is an object with a proper acquisition chain.
The old code only works because of a bug in plone.app.layout: portal_url
is cached ignoring the context. When we want to use the stream as a
tile, the execution order is slightly different and we don't have a
cached value yet, so we see the error.