Skip flaky test TestReadOutdatedInstanceKeys (#13561)

Signed-off-by: Manan Gupta <manan@planetscale.com>

go/vt/vtorc/inst/instance_dao_test.go

@@ -381,6 +381,7 @@ func TestReadInstancesByCondition(t *testing.T) {
 
 // TestReadOutdatedInstanceKeys is used to test the functionality of ReadOutdatedInstanceKeys and verify its failure modes and successes.
 func TestReadOutdatedInstanceKeys(t *testing.T) {
+	t.Skipf("Skipping the test until flakiness can be resolved.")
 	// The test is intended to be used as follows. The initial data is stored into the database. Following this, some specific queries are run that each individual test specifies to get the desired state.
 	tests := []struct {
 		name              string