const runtime.traceBlockUntilGCEnds

3 uses

	runtime (current package)
		mgc.go#L663: 		goparkunlock(&work.sweepWaiters.lock, waitReasonWaitForGCCycle, traceBlockUntilGCEnds, 1)
		traceruntime.go#L104: 	traceBlockUntilGCEnds
		traceruntime.go#L124: 	traceBlockUntilGCEnds:        "wait until GC ends",