Fix track-assignment omission

Forgot to record the track so they sometimes didn't align if
there was a race with finish-transition.

Bug: 279523063
Test: com.android.wm.shell.flicker.splitscreen.SwitchBetweenSplitPairs#cujCompleted
Change-Id: I299f9665395ea146640f213c248d685c8e97b511

services/core/java/com/android/server/wm/TransitionController.java

@@ -963,6 +963,7 @@ class TransitionController {
         if (sync) {
             info.setFlags(info.getFlags() | TransitionInfo.FLAG_SYNC);
         }
+        transition.mAnimationTrack = track;
         info.setTrack(track);
         mTrackCount = Math.max(mTrackCount, track + 1);
     }