Add APEX UIDs to PackageManager query

Because of internal implementation of one way binder calls, in order to
unblock the boot phase, we need to put both the binder call and the
filedescriptor in the background thread.

Original boot time: 17758.6ms
New boot time: 17608.0ms

Bug: 130773130
Test: DeviceBootTest.DeviceBootTest#SuccessiveBootTest
Change-Id: Ib3524418a387c5902af8139e1b2aee82525b8e04