Add temporary CPPLINT.cfg files to libnative{bridge,loader}

This is just to permit moving under art/. We'll back these out after
the move (assuming it's not too much gratuitous churn).

Bug: 141749154
Test: symlink libraries under art/, m cpplint-art-all
Change-Id: Ibd4882f416072076d4605bc329192f0bc1b196fb