Java + Universal Local Runner: combine with hotkey + accumulating mode failure

[damccorm]

On #11792 the following tests failed and were sickbayed:

   excludeTestsMatching 'org.apache.beam.sdk.transforms.CombineTest$BasicTests.testHotKeyCombiningWithAccumulationMode'

Imported from Jira BEAM-10452. Original Jira may contain additional context.
Reported by: kenn.