[split] bump util to 6.9.1-SNAPSHOT

RB_ID=242923
TBR=true
[split] bump util to 6.10.1-SNAPSHOT

RB_ID=251907
TBR=true
[split] bump util to 6.11.1-SNAPSHOT

RB_ID=266347
TBR=true
[split] bump util to 6.11.2-SNAPSHOT

RB_ID=268725
TBR=true
[split] release 6.12.0 of util

RB_ID=288955
TBR=true
[split] release ostrich version 9.3.0

RB_ID=289089
TBR=true
[split] release util version 6.12.1

RB_ID=290145
TBR=true
[split] release ostrich version 9.3.1

RB_ID=290313
TBR=true
Merge branch 'tmp'
Merge remote-tracking branch 'upstream/master' into feature/long-adder
Revert fast histogram implementation to reduce possible stats breakage for existing Ostrich users