Add SElinux policies to allow foreign dex usage tracking.

This is a special profile folder where apps will leave profile markers
for the dex files they load and don't own. System server will read the
markers and decide which apk should be fully compiled instead of
profile guide compiled.

Apps need only to be able to create (touch) files in this directory.
System server needs only to be able to check wheter or not a file with a
given name exists.

Bug: 27334750
Bug: 26080105

Change-Id: I2256e4aba1ec0e5117de6497123223b9a74f404e