Reproducing failure in TestCloudJSONFacetSKGEquiv.testRandom

When running the smoke tester for 9.0 RC4 I hit the following reproducible failure:

./gradlew :solr:core:test --tests "org.apache.solr.search.facet.TestCloudJSONFacetSKGEquiv.testRandom" -Ptests.jvms=5 -Ptests.jvmargs=-XX:TieredStopAtLevel=1 -Ptests.seed=C730F33909C71234 -Ptests.badapples=false -Ptests.file.encoding=UTF-8

Offline discussion with magibney indicates that he has confirmed that although it is an edge case this reaches beyond SKG and was not present in 8 hence blocker.