[#772] node: Apply gofumpt

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

pkg/innerring/processors/netmap/handlers_test.go

@@ -309,12 +309,15 @@ type testEpochState struct {
 func (s *testEpochState) SetEpochCounter(c uint64) {
 	s.counter = c
 }
+
 func (s *testEpochState) EpochCounter() uint64 {
 	return s.counter
 }
+
 func (s *testEpochState) SetEpochDuration(d uint64) {
 	s.duration = d
 }
+
 func (s *testEpochState) EpochDuration() uint64 {
 	return s.duration
 }