Infinite loop during event handling

When a RESET_STATE event causes two other event detectors to trigger simultaneously and discontinuously at the same time then an infinite loop with occur in acceptStep as it tries to backup up and process the one event before the other, but the even time remains the same. This affects integrated and analytical propagators, as well as field versions thereof.

I'm going to try to fix this in time for the 10.2 release.

Originally reported by Mikael in https://forum.orekit.org/t/abstractintegrator-acceptstep-endless-looping-in-eventloop/837