server: use ManualTime in Test_loadEndpoint

This was the only using trying to use this as a hlc.WallClock, which it won't be
when refactored to use crtime.Mono.

Epic: none
Release note: None

Author: stevendanna

pkg/server/load_endpoint_test.go

@@ -127,7 +127,7 @@ func Test_loadEndpoint(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	ctx := context.Background()
 
-	clock := timeutil.NewTestTimeSource()
+	clock := timeutil.NewManualTime(timeutil.Now())
 	rss := status.NewRuntimeStatSampler(ctx, clock)
 	metricSource := newTestMetricSource(clock)
 	le, err := newLoadEndpoint(rss, metricSource)