[RESTRICT AUTOMERGE]Only allow system and same app to apply relinquishTaskIdentity

Any malicious application could hijack tasks by
android:relinquishTaskIdentity. This vulnerability can perform UI
spoofing or spy on user’s activities.

This CL limit the usage which only allow system and same app to apply
relinquishTaskIdentity

Bug: 185810717
Test: atest IntentTests
      atest ActivityStarterTests
      atest TaskRecordTests
Change-Id: I55fe8938cd9a0dd7c0268e1cfec89d4e95eee049
(cherry picked from commit c668064c)