support junction = circular in all profiles, add additional tests

References:
- https://wiki.openstreetmap.org/wiki/Tag:junction%3Dcircular
- https://lists.openstreetmap.org/pipermail/tagging/2016-November/030520.html
- https://github.com/Project-OSRM/osrm-backend/issues/3361

profiles/foot.lua

@@ -156,10 +156,13 @@ function way_function (way, result)
     result.ref = ref
   end
 
-    -- roundabouts
+  -- roundabouts
   if "roundabout" == junction then
     result.roundabout = true
   end
+  if "circular" == junction then
+    result.circular = true
+  end
 
     -- speed
   if route_speeds[route] then