Secure MATCH_UNINSTALLED_PACKAGES across users

Introduce a new internal flag MATCH_ANY_USER for genuine uses
of searching through all apps on the device.

Some temporary accommodations for Launchers that reach across
to the work profile until we have a new LauncherApps API to do
that officially.

Bug: 31000380
Test: CTS tests added
Change-Id: I2e43dc49d6c2e11814a8f8d1eb07ef557f31af34