Catch all exceptions, not just illegal state, when reparenting.

I didn't realize that it can also throw an NPE, and my brain bypassed this information in bug reports. We got there eventually.

Fix: 418628826
Flag: EXEMPT bugfix
Test: atest ActivityTransitionAnimator
Change-Id: I8bfe9f93268032dd68d105fc4c81d5dc130e95c5