tests/robustness: Retry injecting failpoint

Signed-off-by: Marek Siarkowicz <siarkowicz@google.com>

tests/robustness/failpoints.go

@@ -226,14 +226,15 @@ const (
 	Follower  failpointTarget = "Follower"
 )
 
-func (f goPanicFailpoint) Inject(ctx context.Context, t *testing.T, lg *zap.Logger, clus *e2e.EtcdProcessCluster) error {
+func (f goPanicFailpoint) Inject(ctx context.Context, t *testing.T, lg *zap.Logger, clus *e2e.EtcdProcessCluster) (err error) {
 	member := f.pickMember(t, clus)
 
 	for member.IsRunning() {
 		lg.Info("Setting up gofailpoint", zap.String("failpoint", f.Name()))
-		err := member.Failpoints().Setup(ctx, f.failpoint, "panic")
+		err = member.Failpoints().Setup(ctx, f.failpoint, "panic")
 		if err != nil {
 			lg.Info("goFailpoint setup failed", zap.String("failpoint", f.Name()), zap.Error(err))
+			continue
 		}
 		if !member.IsRunning() {
 			// TODO: Check member logs that etcd not running is caused panic caused by proper gofailpoint.
@@ -244,18 +245,22 @@ func (f goPanicFailpoint) Inject(ctx context.Context, t *testing.T, lg *zap.Logg
 			err = f.trigger.Trigger(t, ctx, member, clus)
 			if err != nil {
 				lg.Info("gofailpoint trigger failed", zap.String("failpoint", f.Name()), zap.Error(err))
+				continue
 			}
 		}
 		lg.Info("Waiting for member to exit", zap.String("member", member.Config().Name))
 		err = member.Wait(ctx)
 		if err != nil && !strings.Contains(err.Error(), "unexpected exit code") {
 			lg.Info("Member didn't exit as expected", zap.String("member", member.Config().Name), zap.Error(err))
-			return fmt.Errorf("member didn't exit as expected: %v", err)
+			continue
 		}
 		lg.Info("Member exited as expected", zap.String("member", member.Config().Name))
 	}
+	if err != nil {
+		return fmt.Errorf("member didn't exit as expected: %v", err)
+	}
 
-	err := member.Start(ctx)
+	err = member.Start(ctx)
 	if err != nil {
 		return err
 	}