storage: skip TestNewTruncateDecision

We've identified the root cause, but some cleanup presents itself, and
in the meantime the test is too flaky to leave unskipped.

See cockroachdb#38652.

Touches cockroachdb#38584.

Release note: None

pkg/storage/raft_log_queue_test.go

@@ -463,6 +463,9 @@ func TestNewTruncateDecisionMaxSize(t *testing.T) {
 // removed.
 func TestNewTruncateDecision(t *testing.T) {
  defer leaktest.AfterTest(t)()
+
+ t.Skip("https://github.com/cockroachdb/cockroach/issues/38584")
+
  stopper := stop.NewStopper()
  defer stopper.Stop(context.TODO())
  store, _ := createTestStore(t,