codecs: Add tests to device-tests test_suite

This cherry-picks changes in Android.bp in
media/codecs folder from the commit
f867ca75

Rest of the changes from that commit aren't cherry-picked
as some of those changes are dependent on other CLs that
aren't part of aosp/master and some changes aren't necessary
for enabling native unit tests in mts

Bug: 183561217
Test: Builds
Change-Id: I39867271176a6867ae4ff679a5bbe7c70d5984dd
Merged-In: I32b4233df0f635e9d4ad738b61a5138d9b370f0a