Fix issue with activity reuse for aliased components.

In this case of activity aliases, the ActivityRecord intent
member will contain the aliased component name. The TaskRecord
intent member will contain the resolved component name. When
considering an activity for reuse during start, we need to compare
our candidates ActivityRecord intent, not it's TaskRecord intent
as we have not yet resolved the alias.

Bug: 27112965
Change-Id: Ie3a1fb7b306469037372a0328364ca3d4530599e