Do not reference TaskRecord's intent without checking for null.

It is possible for a TaskRecord's intent to be set to null. We should
always check this before referencing it.

Change-Id: Id0dd18dc694549c348f1cd7d2dfe02915c1c7f92
Fixes: 77457970
Test: atest FrameworksServicesTests:com.android.server.am.TaskRecordTests#testReturnsToHomeStack
5 files changed