Multiple paragraphs in the info macro do not result in multiple lines

First reported in https://forum.xwiki.org/t/new-design-of-boxes/15604/5

{{info}}
There should be
  
two lines.
{{/info}}


{{info}}
There should be

two lines.
{{/info}}

{{info}}
There should be
two lines.
{{/info}}

When there's an empty middle line, the parser interprets the content of the macro as two different paragraphs. This means it does not wrap them together in the same paragraph. We can see that in this situation, the layout is off: we would expect at least a newline between the two paragraphs, but they are both on the same line.