Vendor domains must not use Binder

On PRODUCT_FULL_TREBLE devices, non-vendor domains (except vendor
apps) are not permitted to use Binder. This commit thus:
* groups non-vendor domains using the new "coredomain" attribute,
* adds neverallow rules restricting Binder use to coredomain and
  appdomain only, and
* temporarily exempts the domains which are currently violating this
  rule from this restriction. These domains are grouped using the new
  "binder_in_vendor_violators" attribute. The attribute is needed
  because the types corresponding to violators are not exposed to the
  public policy where the neverallow rules are.

Test: mmm system/sepolicy
Test: Device boots, no new denials
Test: In Chrome, navigate to ip6.me, play a YouTube video
Test: YouTube: play a video
Test: Netflix: play a movie
Test: Google Camera: take a photo, take an HDR+ photo, record video with
      sound, record slow motion video with sound. Confirm videos play
      back fine and with sound.
Bug: 35870313
Change-Id: I0cd1a80b60bcbde358ce0f7a47b90f4435a45c95
diff --git a/private/system_server.te b/private/system_server.te
index d1f9bc3..da1c625 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -3,6 +3,7 @@
 # Most of the framework services run in this process.
 #
 
+typeattribute system_server coredomain;
 typeattribute system_server domain_deprecated;
 typeattribute system_server mlstrustedsubject;