[#772] node: Apply gofumpt

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/innerring/blocktimer_test.go

@@ -117,6 +117,7 @@ type testEpochState struct {
 func (s *testEpochState) EpochCounter() uint64 {
 	return s.counter
 }
+
 func (s *testEpochState) EpochDuration() uint64 {
 	return s.duration
 }