Remove first WaitTaskRun call when creating TR pod

This WaitTaskRun call was moved in a commit but then reinstated the
following day. Looks like this being reinstated was an artifact of a
rebase for a separate PR and the removal of the call was the correct
thing to do.

The original change message for this removal is as follows:

> We can save one goroutines per pod creation by waiting for TaskRun
> only if the pod creation was successful.

This was the original PR with the call removal:
#674

And then it looks like it was reinstated here:
https://github.com/tektoncd/pipeline/pull/648/files#diff-b52b9f382ad878e6aa2a85921bb19065R287

pkg/reconciler/v1alpha1/taskrun/taskrun.go

@@ -284,7 +284,6 @@ func (c *Reconciler) reconcile(ctx context.Context, tr *v1alpha1.TaskRun) error
 		}
 	} else {
 		// Pod is not present, create pod.
-		go c.timeoutHandler.WaitTaskRun(tr)
 		pod, err = c.createPod(tr, rtr.TaskSpec, rtr.TaskName)
 		if err != nil {
 			// This Run has failed, so we need to mark it as failed and stop reconciling it