Prevent activity token leaked to another process

Malicious app could register the organizer via one-way binder call
to disguise as running on pid 0.

Bug: 367266072
Test: verified via the sample app
Flag: EXEMPT bugfix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:61ab2b65caf855c48fdb4166f94e02bf79c90e7b)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:6ab778a0dd3d09c6e3e2b6176245d3c99b5170ce)
Merged-In: I51378c7d2da06fb83670abd082a089cfd82d699d
Change-Id: I51378c7d2da06fb83670abd082a089cfd82d699d