Allow core uids to register receiver as "android".

System components can run in any processes belonging to core uids. If
one of such components end up registering a receiver, it will get
registered as "android".

Bug: 387930030
Bug: 310632322
Test: builds
Flag: EXEMPT bugfix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:252bdb73a318ceccc7391106271b7f233f165810)
Merged-In: Ia577940331af5a79804aa6afcd1773e207a58558
Change-Id: Ia577940331af5a79804aa6afcd1773e207a58558