tests: replace godebug by go-cmp for structure diffs

go-cmp is stricter and allow to catch more problems. Moreover, the
output is a bit nicer.

console/tests.go

@@ -9,6 +9,8 @@ import (
 	"testing"
 
 	"github.com/benbjohnson/clock"
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 
 	"akvorado/common/clickhousedb"
 	"akvorado/common/clickhousedb/mocks"
@@ -43,3 +45,8 @@ func NewMock(t *testing.T, config Configuration) (*Component, *httpserver.Compon
 	helpers.StartStop(t, c)
 	return c, h, mockConn, mockClock
 }
+
+func init() {
+	helpers.RegisterCmpOption(cmpopts.IgnoreUnexported(graphCommonHandlerInput{}))
+	helpers.RegisterCmpOption(cmp.AllowUnexported(graphLineHandlerInput{}))
+}