Retrieve cached run for the tasks view

Address the issue of outdated active test data in the run retrieved
from the database, which is particularly noticeable in the chi2 residuals.

Fixed the Nginx config to serve the route /tests/tasks
from the main Fishtest instance.

server/fishtest/views.py

@@ -1411,10 +1411,7 @@ def tests_stats(request):
 
 @view_config(route_name="tests_tasks", renderer="tasks.mak")
 def tests_tasks(request):
-    r_id = request.matchdict["id"]
-    run = request.rundb.runs.find_one(
-        {"_id": ObjectId(r_id)}, {"tasks": 1, "bad_tasks": 1, "results": 1, "args": 1}
-    )
+    run = request.rundb.get_run(request.matchdict["id"])
     if run is None:
         raise exception_response(404)