Ensure that participated activities are not omitted by ancestor

... when preparing transition targets.

Previously, the first step of the calculation finds the top participant
if possible, and once there is one, only the level above task will be
added. Because it assumes that the parent of participant can represent
it. But there are more than one participants belong to an ancestor, the
descendants may have individual changes, so they should be still in the
transition targets. Otherwise the animation may have nothing to do.

Now all valid participants are added into the target lists, and then
combine the targets from bottom to up based on depth. So it can be
done in 1 pass (originally it requires 3 passes when launching a new
task from home, 4 passes when starting recents).

The population of ChangeInfo#mParent is moved after tryPromo so it
can skip the targets which were removed, and the parent info can
be updated in a single place.

Bug: 213867980
Test: TransitionTests#testOpenActivityInTheSameTaskWithDisplayChange
Test: adb shell setprop persist.debug.shell_transit 1; reboot
      Start a landscape activity from a portrait activity in the
      same task. The animation should not jump cut.

Change-Id: I23a3326611dcb5664b204748280ae15b2377f318