Problem

jstests/replsets/remove_newly_added_field_after_finishing_initial_sync.js's local stepUpNode() helper calls replSetStepUp once with no retry. A real election can legitimately fail even after its dry run succeeds (a "spoiled vote" when the responder's concurrent stepdown interrupts its LastVote write — see ReplicationCoordinatorImpl::processReplSetRequestVotes, already covered by NodeFailsVoteRequestIfItFailsToStoreLastVote). This is exactly why ReplSetTest.stepUp() wraps the same call in assert.soonNoExcept(); this test's homegrown helper doesn't, causing intermittent failures.

Fix

Wrap the replSetStepUp call in stepUpNode() in assert.soonNoExcept(), matching ReplSetTest.stepUp(). Test-only change, no server behavior change.