Run AppSecurityTests in postsubmit.

Because we care if they break.

Putting the change here because this covers changes in at least
android/content/pm and services/core/.../pm (the latter has a
TEST_MAPPING that imports this one).

Test: atest :postsubmit
Bug: 137951074
Change-Id: Ie03397c857d6a94702549ba325631558ed04a9db