flake on optimization test

[johnynek]

.[info] - all optimization rules do not increase steps *** FAILED ***
[1435](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1435)
[info]   TestFailedException was thrown during property evaluation.
[1436](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1436)
[info]     Message: 2 was not greater than or equal to 3
[1437](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1437)
[info]     Location: (OptimizationRulesTest.scala:333)
[1438](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1438)
[info]     Occurred when passed generated values (
[1439](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1439)
[info]       arg0 = WithDescriptionTypedPipe(MergedTypedPipe(WithDescriptionTypedPipe(Fork(WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(CrossPipe(WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(Mapped(EmptyTypedPipe,<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),WithDescriptionTypedPipe(FlatMapped(WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(Mapped(CoGroupedPipe(Pair(IdentityReduce(scala.math.Ordering$Int$@9334f56e,WithDescriptionTypedPipe(WithDescriptionTypedPipe(FlatMapped(EmptyTypedPipe,<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),None,List(),ReflexiveEquality()),IdentityReduce(scala.math.Ordering$Int$@9334f56e,WithDescriptionTypedPipe(WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(MergedTypedPipe(EmptyTypedPipe,WithDescriptionTypedPipe(MergedTypedPipe(EmptyTypedPipe,EmptyTypedPipe),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true)))),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),None,List(),ReflexiveEquality()),<function3>)),<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true)))),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),<function1>),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true)))),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),EmptyTypedPipe),List((org.scalacheck.Gen$R$class.map(Gen.scala:237),true))),
[1440](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1440)
[info]       arg1 = com.twitter.scalding.typed.OptimizationRules$ComposeDescriptions$@57aba9bd.orElse(com.twitter.scalding.typed.OptimizationRules$ComposeFlatMap$@b3cc04f4).orElse(com.twitter.scalding.typed.OptimizationRules$ComposeMap$@ae1e2d3b).orElse(com.twitter.scalding.typed.OptimizationRules$ComposeFilter$@95782a9d).orElse(com.twitter.scalding.typed.OptimizationRules$ComposeWithOnComplete$@68e48373).orElse(com.twitter.scalding.typed.OptimizationRules$MapValuesInReducers$@b76c7b32).orElse(com.twitter.scalding.typed.OptimizationRules$ComposeFilterFlatMap$@c9cdd75b).orElse(com.twitter.scalding.typed.OptimizationRules$ComposeFilterMap$@c6f9cd4f).orElse(com.twitter.scalding.typed.OptimizationRules$ComposeReduceSteps$@a7568d99).orElse(com.twitter.scalding.typed.OptimizationRules$DescribeLater$@71290125).orElse(com.twitter.scalding.typed.OptimizationRules$EmptyIterableIsEmpty$@237ffbb9).orElse(com.twitter.scalding.typed.OptimizationRules$RemoveDuplicateForceFork$@f7a0576a).orElse(com.twitter.scalding.typed.OptimizationRules$IgnoreNoOpGroup$@abf66222).orElse(com.twitter.scalding.typed.OptimizationRules$DeferMerge$@8d5f3a4f).orElse(com.twitter.scalding.typed.OptimizationRules$FilterKeysEarly$@c7f6e49e).orElse(com.twitter.scalding.typed.OptimizationRules$FilterLocally$@4a396162)
[1441](https://github.com/twitter/scalding/runs/5505683474?check_suite_focus=true#step:7:1441)
[info]     )

[johnynek]

 [info] - all optimization rules do not increase steps *** FAILED ***
[info]   TestFailedException was thrown during property evaluation.
[info]     Message: 1 was not greater than or equal to 2
[info]     Location: (OptimizationRulesTest.scala:329)
[info]     Occurred when passed generated values (
[info]       arg0 = WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(CrossPipe(WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(Filter(IterablePipe(List(-2147483648, 1781964488)),org.scalacheck.GenArities$$Lambda$2891/0x0000000000000000@3d51d390),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),org.scalacheck.GenArities$$Lambda$2891/0x0000000000000000@83722857),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),WithDescriptionTypedPipe(FlatMapped(WithDescriptionTypedPipe(FlatMapped(WithDescriptionTypedPipe(Mapped(WithDescriptionTypedPipe(Filter(IterablePipe(List(-626853775, -1478385954)),org.scalacheck.GenArities$$Lambda$2891/0x0000000000000000@54eae19e),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),org.scalacheck.GenArities$$Lambda$2891/0x0000000000000000@1b725c5d),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),scala.Function1$$Lambda$335/0x0000000000000000@68d1bf),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),scala.Function1$$Lambda$335/0x0000000000000000@e869947f),List((org.scalacheck.Gen$R.map(Gen.scala:237),true)))),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),<function1>),List((org.scalacheck.Gen$R.map(Gen.scala:237),true))),
[info]       arg1 = com.twitter.scalding.typed.OptimizationRules$MapValuesInReducers$@1b206480.orElse(com.twitter.scalding.typed.OptimizationRules$FilterKeysEarly$@c6bc460e).orElse(com.twitter.scalding.typed.OptimizationRules$FilterLocally$@b702f5df)
[info]     )