[TEST] upgrade randomized runner to 2.1.11

2.1.11 contains the fix for this issue: https://github.com/carrotsearch/randomizedtesting/issues/179

Closes #8930
Function score and optional weight : avg score is wrong #8992
(cherry picked from commit 025118e)
Merge branch '1.4' of https://github.com/elasticsearch/elasticsearch into 1.4
rename count as weightSum
fix spaces formatting
rename weightsSum as weightSum